All Tools

Mortgage calculator — monthly payment, total interest, amortization schedule, early payoff scenarios.

Loan comparison calculator — compare equal-payment vs equal-principal, multiple loans side by side, total interest breakdown.

Loan prepayment calculator — see how much interest you save by paying extra each month or one-time, with breakeven analysis.

Annuity & retirement calculator — see monthly income from your savings, accumulation + payout phases, multiple scenarios.

Compound interest calculator — see how money grows over time, with monthly contributions, charts, and breakdown.

Savings goal tracker — set a target (down payment, trip, emergency fund), see weekly/monthly contribution and projected date.

China personal income tax calculator — monthly, annual, with 5 insurance + 1 fund deductions.

China company income tax calculator — small/micro (2.5%/5%/25%) vs general taxpayer, R&D super-deduction, loss carry-forward 5 years.

China personal income tax special deduction simulator — 7 categories (kids/elder/mortgage/rent/education/medical/infant), year-end reconciliation included.

China vehicle purchase tax calculator — 10% rate on tax-exclusive price, with NEV exemption rules, plus on-road cost breakdown.

China second-hand house transaction tax calculator — contract tax + VAT + personal income tax + agency fee + transfer fee, by city + house tenure + family situation.

Property fee calculator — calculate Chinese residential management fees, garage, heating, elevator, with regional rate references.

Currency converter — 50+ currencies with offline reference rates, convert without internet, source data updated each release.

Expense tracker — log spend, categorize, see monthly totals, all in your browser.

Wedding budget planner — itemized cost calculator with regional benchmarks for venue, photography, catering, etc.

Kids allowance calculator — age-appropriate weekly/monthly amount with chore-based breakdown, savings goal sandbox.

Tip & split calculator — calculate tip by percentage, split bill among friends, round-up options, multi-currency.

Meeting cost calculator — see how much that meeting is costing in real-time, with team salary data and overhead multiplier.

Car loan calculator with prepayment — bank vs 4S dealer financing comparison, equal-installment / equal-principal / balloon plans, prepayment-savings simulation.

Estimate daily and monthly LLM spend from tokens, request volume, and editable model prices.

China housing-provident-fund loan calculator — single + dual contributor max loan, monthly payment (equal-principal + equal-installment), top-30 cities 2025 caps.

China pension calculator — basic + personal-account + transitional pension formulas (2024 reform), by province average wage, contribution years, base, with 2055 projection.

China used-car price estimator — depreciation curve by brand tier + age + mileage + condition, plus 4S trade-in vs private vs auction net comparison.

China unemployment benefits calculator — monthly amount + total months by city + insurance years, per 2026 policy.

China overtime pay calculator — workday 1.5×, weekend 2×, statutory holiday 3× per Labor Law Art. 44, with 31 provincial minimum-wage tables.

Body Mass Index calculator with WHO + Asian classifications — metric and imperial — browser-only

BMR calculator — basal metabolic rate by Mifflin-St Jeor and Harris-Benedict (compared side-by-side).

Calorie calculator — daily calorie needs (BMR + TDEE), weight loss/gain targets, macro breakdown.

Body fat % calculator — 4 formulas (US Navy / BMI-based / YMCA / Jackson-Pollock) with body shape visualization.

Water intake calculator — daily water target by body weight, activity, climate. With drink-log to track today's progress.

Protein intake calculator — daily grams by body weight, activity, goal (cut/maintain/bulk), per ISSN 2017 guidelines.

Macro nutrient calculator — TDEE + protein/fat/carb split for cut/maintain/bulk goals, with 3 split presets (high-protein/keto/balanced) and meal example.

Intermittent fasting tracker — 16:8 / 18:6 / 20:4 / OMAD / 5:2 / 36h timer with stages and history log.

Weight loss tracker — set target, log daily weight, see trend, project goal date with real calorie math.

Weight training tracker — log compound lifts (squat/bench/deadlift/OHP), track 1RM via Epley formula, see strength gains by week.

Strength 1RM calculator + training program — 6 formulas (Epley/Brzycki/Lombardi/O'Conner/Lander/Mayhew), %1RM table, Wendler 5/3/1 + Sheiko + Madcow templates.

Heart rate zones calculator — max HR (4 formulas) + 5 training zones (recovery/aerobic/tempo/threshold/VO2max), with workout examples.

Stair climbing calorie calculator — calculate kcal burned by floors climbed, with METs-based formula.

Running pace calculator — convert between pace / time / distance, predict 5K/10K/half/full marathon from one race.

Marathon time predictor — input 5k/10k/half time, get full marathon prediction via 3 formulas (Riegel/Cameron/VDOT), with pace zones and weekly mileage advice.

Sleep cycle calculator — 90-minute REM cycles. Find best bedtime if you must wake at X, or best wake time if you sleep at Y.

Sleep debt calculator — track this week's sleep hours, see your accumulated debt, get a realistic recovery plan based on research.

Ovulation & fertility tracker — predict next 6 months of fertile windows, track BBT, find best conception days.

Period & ovulation calculator — predict next period, fertile window, safe days (based on calendar method).

Pregnancy due date calculator — track weeks, trimester, baby development by week.

China maternity benefits calculator — leave days by province (98 base + extension 30-180 days), maternity allowance (avg-wage × leave-days / 30), medical reimbursement, 2025 policy.

Child adult-height predictor — 3 scientific methods (mid-parental / Khamis-Roche / CDC growth percentile), with confidence range + growth chart.

China 0-6y child immunization schedule — 11 free + 12 paid vaccines, generates personalized calendar from baby's birthdate, with per-dose reminders.

Calculate your exact age — years, months, days, hours. Compare two dates or count to a future date.

Days / weeks / months / years between two dates — plus business-days mode — browser-only

Countdown timer — to any date and event, with live ticking down to seconds.

Work tenure calculator — service years, annual leave entitlement (China), retirement countdown.

Convert any time between any two timezones — DST-aware, IANA database — browser-only

Plan meetings across timezones — see when everyone's working hours overlap.

Cooking unit converter — tsp / tbsp / cup / oz / ml / g for 100+ common ingredients with density.

Recipe scaler — paste any recipe, change servings, get all ingredient amounts auto-scaled. Handles fractions and unit conversion.

Fish tank size calculator — input fish species and count, get the minimum tank gallons/liters needed and stocking density warnings.

Pet age calculator — accurate dog/cat human-age equivalent, with breed size adjustment, lifespan stages.

Pet food calculator — RER + activity factor for dogs and cats, exact daily grams based on weight, age, neuter status, and kibble kcal/100g.

Screen time budget — track and visualize daily screen time across phone/tablet/PC, with age-based recommendations from WHO/AAP.

BPM tap counter — tap the spacebar to the beat, instantly get tempo with running average, find your song's tempo for DJ / dance / metronome.

Typing speed test — WPM, accuracy, real-time mistakes, English + Chinese pinyin modes.

Airline luggage allowance — 50+ carriers' carry-on / checked baggage rules with size, weight, and excess fee.

China drunk-driving penalty reference — BAC threshold (20/80), license suspension/revocation, criminal charges, insurance impact, by scenario.

China three-child birth subsidy policy finder — per province / city one-time + monthly + housing + education subsidies (2024-2025 latest).

Pomodoro timer — 25/5 classic, plus 50/10 and 90/15 long-focus modes, with sound, browser tab title, daily stats.

Scientific calculator — sin / cos / log / sqrt / power, with full keyboard input + history, deg/rad mode.

Convert between length, weight, temperature, area, volume, speed, time — instant, browser-only

5 common percentage calculations — "x% of y", "x is what% of y", percentage change, increase/decrease — instant, browser-only

Generate cryptographically-secure random integers — single or batch, with/without duplicates — browser-only

Math formula reference — algebra, geometry, trigonometry, calculus, statistics, all in one place.

Interactive periodic table — 118 elements, properties, electron config, search.

Birthday paradox calculator — see the probability of shared birthdays in a group of N people, visualized step by step.

Calculate aspect ratio — fix any 1 of [width, height, ratio], get the other two.

Number base converter — binary, octal, decimal, hex, and any base 2-36. Bitwise too.

Complex number calculator — +-×÷ + conjugate + modulus + argument + polar/Cartesian conversion + powers + roots + Euler form, complex plane visualization.

Matrix calculator — add/sub/multiply/inverse/determinant/transpose/rank/RREF/eigenvalues for n×m matrices, step-by-step.

Quadratic equation solver — ax² + bx + c = 0, discriminant analysis, real + complex roots, vertex/intercepts, parabola visualization.

Trigonometry calculator — sin/cos/tan + inverse + sec/csc/cot, degree/radian/gradient, unit circle visualization, exact values.

Derivative calculator with step-by-step — symbolic differentiation, chain/product/quotient rule shown, plot f(x) and f'(x).

Indefinite integral calculator step-by-step — symbolic integration, substitution + integration by parts shown, plot f(x) and F(x).

Basic statistics calculator — mean/median/mode/variance/std-dev/quartiles/range/IQR/skewness/kurtosis + histogram + box plot, paste any numbers.

Probability distribution visualizer — normal/t/chi-sq/F/binomial/poisson/exp/uniform PDF+CDF, P(a≤X≤b) area, z/p table replacement.

Chemistry equation balancer — paste an unbalanced equation, solve coefficients using the matrix method, show step-by-step.

Linux permission (chmod) calculator — convert between octal (755), symbolic (rwxr-xr-x), and ls -l forms, with safety warnings.

CSS px ↔ rem ↔ em converter — visual scale, base font size adjustable.

Unix timestamp ⇄ human date — seconds / milliseconds / ISO 8601 — UTC and local — browser-only

IELTS band calculator — convert listening/reading raw scores to band, average four skills, see your overall band.

MBTI quick test — 28 questions, 5 minutes, get your 4-letter type with detailed reading.

College major matcher — Holland code (RIASEC) test, 40 questions, recommend 10+ matching majors with career path.

China gaokao major recommender 2026 — filter by score range + subject combo (3+1+2) + interest + employment outlook, 150+ undergrad majors across 12 disciplines.

BaZi (Four Pillars) calculator — Chinese metaphysics birth chart with 8 characters, five elements analysis.

Chinese zodiac checker — your animal sign, element, compatibility, lucky numbers/colors by birth year.

Chinese zodiac fortune — daily/monthly/yearly outlook for 12 zodiac signs in love, career, wealth, health.

Chinese zodiac compatibility — match two people by their zodiac signs, 144 pair combinations with reading.

Western zodiac calculator — your sign, element, ruling planet, compatibility, daily traits.

Gregorian ⇄ Chinese Lunar (Nongli) calendar — bi-directional, accurate 1900-2100.

Arabic ⇄ Chinese number — simple (一二三), formal (壹貳參), or amount (金额大写 with 元角分).

Chinese character stroke counter — count strokes for any hanzi, traditional or simplified.

Chinese lunar almanac (huangli) — daily 宜/忌 advice, 24 solar terms, 干支/生肖, auspicious hours, any date 1900-2100.

China marriage betrothal reference — 30+ provinces' typical betrothal money + dowry + 3-gold/5-gold averages (2024-2026 public data).

China retirement age calculator (2025 reform) — exact retirement date by birth year + gender + worker category, per Sept 2024 NPC reform.

Color mixer — blend any two colors with adjustable ratio, RGB/HSL/LAB color space, predict the result and copy hex.

24-point solver and game — enter 4 numbers and get every solution instantly, or play random hands against the clock.

Add or subtract days, weeks, months, and years from any date — plus a business-day mode that skips weekends. Runs entirely in your browser.

The exact gap between two birthdays — years/months/days, percentage, and the date one person is twice the other's age — browser-only

AI token counter — estimate token count for GPT / Claude / Gemini, with per-model cost calculator (2026 pricing).

Convert nominal APR to effective APY (and back) at any compounding frequency — daily, monthly, quarterly, or continuous. Two-way, instant, browser-only.

Widmark-formula BAC estimate from drinks, body weight, sex and time — educational only, never a fit-to-drive verdict — browser-only

Thickness × width × length ÷ 12 = board feet — multi-row cut list, per-BF cost, imperial ⇄ m³ — browser-only

How many units must you sell to stop losing money? Enter fixed costs, price, and variable cost per unit for break-even units, break-even revenue, and contribution margin — browser-only

Room area × ceiling × orientation × people → cooling BTU/h, 匹 (horsepower) and kW — sizes an AC right the first time — browser-only.

Working days between two dates, or a date N working days out — weekends + holidays excluded, browser-only

Track how much caffeine is still in your system, how much is left at bedtime, and when it drops to a sleep-friendly level — half-life model, browser-only.

Pick a daily calorie deficit, enter your current and goal weight, and see how many weeks it takes and the date you'd hit your target — with a safety check, browser-only

MET-based calorie burn for 30+ activities — running, cycling, swimming, HIIT, housework — stack and total — browser-only

Cap cost, residual, money factor, term → exact monthly payment with depreciation + finance + tax breakdown — 100% in your browser

Rooms + roll width + waste → linear metres, billed area (m² / ft² / sq yard) and cost — browser-only

Certificate of Deposit maturity, interest & effective APY — APY or APR + compounding, early-withdrawal penalty, CD ladder — browser-only

US ⇄ UK ⇄ EU ⇄ CN ⇄ S–XXL for men & women — tops, trousers, dresses, suits — with the body measurements behind every size — browser-only

Coffee-to-water ratio calculator — type 1:16, pick a brew method, get exact grams of coffee and water for any batch

nPr, nCr, n!, n^r and combinations-with-repetition — exact BigInt results with the formula and worked steps — browser-only

Work out sales commission three ways — flat rate, progressive tiers, or reverse-solve the sales you need to hit an income target. Browser-only, shareable.

Slab, column, round footing & stairs → cubic meters/yards + cement bags, sand and gravel — browser-only

Net profit, ROI%, fees, and the break-even sell price for a crypto trade — enter by quantity or by amount invested, both buy and sell fees counted — browser-only

How many days until a date — plus weeks, months, business days, exact remaining, and the weekday it lands on

Snowball vs avalanche — payoff date, total interest, and what an extra payment saves — browser-only

Solve ρ = m / V for density, mass, or volume · mixed units (g, kg, lb, mL, L, cm³, gallon) · 20 substance presets · floats-or-sinks verdict — all browser-only

Near limit, far limit, total depth of field & hyperfocal distance from your sensor, focal length, aperture and focus distance — browser-only

Solve C1V1 = C2V2 and ratio dilutions (1:10) — stock + water amounts in mL / L / fl oz / gal — browser-only

Sale price, amount saved, % off — plus stacked discounts, BOGO, spend-X-save-Y, tax, and reverse % — instant, browser-only

Share price + annual dividend → yield %, annual/quarterly/monthly income, and yield on cost after years of dividend growth — browser-only

Wall + ceiling area → sheets, drywall screws, joint tape & compound — metric and imperial — browser-only

Seconds ⇄ minutes ⇄ hours ⇄ days ⇄ weeks, plus human-readable, ISO 8601 duration and HH:MM:SS — one input, every format — browser-only

Power × hours × tariff → kWh and cost per day, month, and year — add multiple appliances, account for standby — browser-only.

Battery kWh + charge % + tariff → cost per charge, per 100km/mile, and how much you save vs petrol — browser-only

Total run + post spacing → posts, panels/pickets, rails, concrete bags — metric & imperial — browser-only

Current grade + final weight + target → exactly what you need on the final — browser-only

Room sizes + flooring type + box coverage + waste → net area, boxes, planks, and cost — metric or imperial, browser-only.

Add, subtract, multiply, divide fractions — auto-reduced, with steps, mixed ⇄ improper ⇄ decimal — browser-only

Back into the hourly rate you must charge from your target salary, business expenses, billable hours, profit margin, and taxes — browser-only

Trip fuel cost from distance + economy + price — round trip, per-person split, L/100km ⇄ MPG — browser-only.

Project the future value of a lump sum plus regular contributions — full time-value-of-money math, year-by-year, browser-only

2048 game — slide tiles, combine numbers, reach 2048. Pure browser, no ads, your high score saved locally.

GCD + LCM of any list of integers — Euclidean steps, prime factorization, prime-factor table — exact BigInt math, browser-only

Gear & transmission ratio plus bicycle gear inches, development and speed from cadence — exact, browser-only

Split any length by φ = 1.618 — long/short segments, golden sequence, font scale, layout columns, golden rectangle — browser-only

Weighted GPA from courses + credits + grades — US 4.0 / 4.3 and China 4.0 / 4.5 conversion, letter ⇄ percentage ⇄ point — browser-only

Weighted course grade + what you need on the final — multi-row categories, letter grade, shareable link — browser-only

Lawn area + species + new/overseed → exact seed weight and bag count — metric & US — browser-only

Area + depth → volume, tonnes, bulk bags — driveways, drainage, paths — browser-only

Solve any radioactive-decay unknown — initial amount, remaining amount, elapsed time, or half-life — with exact exponential math, all in your browser

Air temperature + humidity to the real "feels-like" temperature, with NWS risk level — exact Rothfusz regression, browser-only

Income + debt + down payment + rate → the max home price a lender's 28/36 rule will actually approve — browser-only

Solve PV = nRT for pressure, volume, amount, or temperature — pick any unknown, mix any units, runs in your browser

Devine + Robinson + Miller + Hamwi formulas, side by side, plus the healthy BMI weight band — metric and imperial — browser-only

See what your money is really worth — future value, purchasing power, and the rule-of-72 halving point, all from one inflation rate

Find duplicates and keep one clean copy of iso dates from pasted text or uploaded local files.

Extract, dedupe, and export iso dates from pasted text or uploaded local files.

Convert iso dates from pasted text or uploaded local files.

Validate and explain issues in iso dates from pasted text or uploaded local files.

Normalize, sort, and prepare iso dates from pasted text or uploaded local files.

Estimate how many days jet lag will last and build a day-by-day plan to pre-shift your body clock before you fly — eastbound vs westbound, light and melatonin timing, all in your browser

Cost ⇄ price ⇄ markup % ⇄ margin % — solve any two, see both rates side by side — 100% in your browser

a mod n in both conventions — the % your language returns AND the math mod that is never negative, plus floor quotient, modular power and inverse

Type any chemical formula — get molar mass, a per-element mass-percent table, and mass↔mole conversion. IUPAC weights, browser-only.

Distance + fuel → MPG (US/UK), L/100km, km/L, all at once + cost per mile/km — browser-only

Garden bed area + spread depth → cubic yards, bags and bulk — multi-bed, metric/imperial — browser-only

Add up assets, subtract debts, see your real net worth — with a debt-to-asset ratio and composition bars, all computed in your browser

Note name ⇄ frequency (Hz) — A4 = 440/432/442, MIDI number, cents off — browser-only

One number in, every format out: thousands grouping, currency, percent, scientific, engineering, compact (K/M/万), ordinal, byte size — plus reverse parsing. 100% browser-only.

Enter any two of voltage, current, resistance, or power — get the other two plus the formula used — with mV/V/kV, µA/mA/A, Ω/kΩ/MΩ, mW/W/kW prefixes — browser-only.

Estimate your 1RM from any set with five formulas at once, then read a full %1RM training-load table — kg or lb, browser-only

Wall area → litres & cans of paint, with doors/windows deducted, coats and price — metric & US units, browser-only

Stripe, PayPal, Square fees — see what lands in your account, and gross-up to net any target — 100% in your browser

Compare a measured value against the true value — get percent error, absolute error, relative error, and signed high/low. Plus a percent-difference mode for two trials with no accepted answer.

Growth rate, drop, percentage-point gap, and reverse-solve the new value — signed, color-coded, browser-only

Baker's percentage pizza dough — flour, water, salt, yeast, oil by weight — browser-only

Bed size + in-row & row spacing → exact plant count — square vs triangular layout — browser-only

Target weight → exactly which plates to slide on each end — kg & lb, with a live barbell diagram — browser-only

Find how many gallons (and liters and cubic meters) your pool holds — rectangle, round, oval, or sloped floor — in feet or meters

Pixel density, dot pitch, physical size, aspect ratio & a retina check from resolution + diagonal — all in your browser

Pre-pregnancy BMI + week → IOM recommended total gain, the by-week target, and an on-track check — singleton & twins — browser-only

Test primality · factorize · list primes in a range · find the N-th prime — exact BigInt math, browser-only

Solve flight time, max height, range & impact speed from launch speed, angle and height — with a live trajectory plot, browser-only

Solve a²+b²=c² — find the hypotenuse, find a missing leg, or measure the distance between two points (2D & 3D). Browser-only.

Solve a:b = c:x, simplify ratios, split a total by a ratio, scale a recipe up or down — with full steps, browser-only

How much rent can you actually afford? 30% rule, landlord 3× gate, and a debt-aware 50/30/20 number — all client-side

See whether buying beats renting and investing the difference — net cost, terminal equity, and the break-even year, all in your browser

Decode 4, 5 and 6-band resistors to Ω, tolerance and tempco — or go the other way, with a live color-band drawing

Project your retirement pot from age, savings, monthly contributions, return and inflation — with a 4% safe-withdrawal income, growth curve, and goal-gap check. Browser-only.

US ⇄ UK ⇄ EU ⇄ JP ⇄ CN ⇄ inner circumference & diameter (mm) — type any one, get every size at once — browser-only

ROI %, net gain, annualized ROI (CAGR) and payback period — one screen, share a link — 100% in your browser

Arabic ⇄ Roman, both directions, live — strict validation, step-by-step breakdown, vinculum up to 3,999,999 — 100% browser-only

Roof footprint + pitch → real sloped area, roofing squares, shingle bundles or sheets and underlayment rolls — metric & US, browser-only

Estimate doubling time from a rate (72 ÷ r), or the rate from a target time — side by side with the exact ln(2)/ln(1+r) figure — browser-only

Turn a raise into real numbers — new salary by year/month/hour, dollar increase, and the inflation-adjusted raise that tells you if you actually came out ahead

Hourly ⇄ daily ⇄ weekly ⇄ monthly ⇄ annual pay — set your hours/week and weeks/year, see all five at once — browser-only

Add or remove US sales tax — split state + local rates, real 2024 state base rates on tap, browser-only

Plain ⇄ scientific (a×10ⁿ) ⇄ engineering ⇄ E-notation — with significant figures, exact big/small numbers — browser-only

US ⇄ UK ⇄ EU ⇄ CN ⇄ JP + foot length (cm/in) — men, women, kids — browser-only

Count sig figs · round to N significant figures · do sig-fig arithmetic — exact string-level math, browser-only

I = P × r × t — solve for interest, principal, rate, or time, plus total and a simple-vs-compound gap — browser-only

Two points in, full line out — slope, angle, distance, midpoint, y = mx + b and grade % — browser-only

Add every room, get one total in ft² and m² at once — waste % + cost — browser-only

Total rise + steps → rise/run, slope, Blondel comfort check + side-view diagram — metric & imperial, browser-only

Sudoku generator and solver — 4 difficulties (easy / medium / hard / expert), unique-solution guaranteed, play in the browser or print as PDF.

Gross → net pay, any country — your own tax rate, pre-tax & post-tax deductions, reverse-solve — browser-only

TDEE calculator — BMR × activity factor, with cut/bulk calorie targets and projected weekly weight change.

Turn any BPM into a full delay-time table — milliseconds and Hz for every note value, plus dotted and triplet. Built for mixing and producing.

Answers wrong → percent + letter grade + a full printable grading chart — the teacher's EZ Grader, browser-only

Room area + tile size + grout joint + waste → tiles, boxes, and cost — metric or imperial, browser-only.

Weekly time card — clock in/out + lunch → daily hours, weekly total, gross pay, 40h overtime — browser-only

Hours between two times, add or subtract time, and add up a timesheet — decimal hours + pay — browser-only

Decode 225/45R17 into diameter, sidewall, circumference & revs/km — then compare two tires for speedometer error and clearance change. Browser-only.

Triangle solver — SSS, SAS, ASA, AAS, and the ambiguous SSA case via law of sines + law of cosines. All sides, angles, area, perimeter, type, drawn to scale.

Split group trip, dinner & shared-flat costs — track who paid what, who joined which expense, and get the fewest transfers to settle up. 100% in your browser.

Add tax, remove tax, or find the rate — net ⇄ gross at any VAT / GST / sales-tax rate — instant, browser-only

Estimate your maximal oxygen uptake from four field tests — Cooper run, 1.5-mile, resting HR, Rockport walk — with a fitness grade by age and sex

WHR = waist ÷ hip, scored against the WHO health-risk bands by sex, with an optional waist-to-height check — runs entirely in your browser

Wall size + roll spec + pattern repeat → strips per roll, total strips, rolls to buy — handles straight & half-drop match — browser-only

Convert between wavelength λ, frequency f, and photon energy E · c = λf · E = hf · spectrum band + visible colour · browser-only

What week number is today? ISO 8601 (Mon-start) + US (Sun-start), plus year + week → date range — browser-only

Items + weights → your current course grade, with letter and banked points — browser-only

Turn air temperature and wind speed into a feels-like number — and a frostbite warning — using the official NWS / Environment Canada formula. Metric or imperial, browser-only.

Standardize any value, reverse a z-score back to raw, or compute μ and σ from a dataset — with left/right/two-tailed normal probabilities and percentile

Chinese characters to pinyin — with tone marks or numbers, supports simplified and traditional.

800+ everyday chengyu — pinyin, origin, usage.

Chinese classical poetry — 300+ hand-annotated Tang/Song/Yuan canon (唐诗宋词元曲) plus 80,000+ searchable Tang/Song/Shijing/Chuci poems on demand.

Chinese name generator — meaningful Chinese names with pinyin, meaning, and stroke count.

Chinese character stroke counter — count strokes for any hanzi, traditional or simplified.

Chengyu chain game with a 30,000+ idiom dictionary (full 汉语成语大词典 coverage). Start with any idiom; the computer continues with one whose first character matches your last.

Traditional ⇄ Simplified Chinese — fast, character-level, no API.

Five Elements (Wuxing) name recommender — based on Bazi gaps, suggest characters that balance the missing elements.

Handwriting practice sheet generator — Chinese 米字格 / 田字格 / 四线三格 (English) PDF-ready printable.

English vocabulary test — estimate your vocab size in 5 minutes, levels CET-4 / CET-6 / IELTS / TOEFL / GRE.

English grammar rules reference — 60+ core grammar rules with side-by-side examples, common mistakes, bilingual explanations.

English collocations reference — 200+ common verb + noun / adj + noun / verb + prep collocations with usage examples.

English irregular verbs reference — 200+ verbs with base / past / past participle, Chinese gloss, in-browser audio, pattern filter, and a flash-card practice mode.

HSK Chinese vocabulary test — estimate your Mandarin level (HSK 1-6) in 5 minutes with real exam words.

Arabic 500 essential A1–A2 MSA words — Arabic script with full ḥarakāt, DIN 31635 romanization, gender, three-form verbs, audio TTS.

Dutch 500 essential A1–A2 words — IPA + de/het articles + 6-person conjugation + audio TTS.

600 French words covering the full DELF A1-A2 référentiel plus B1 core — IPA, gender, full Bescherelle conjugation (présent, passé composé, futur simple), free TTS audio, 16 life-context categories.

German 500 essential words (A1-A2 + B1 core) with IPA, der/die/das, full Präsens, Präteritum, Perfekt, Partizip II for verbs, and browser TTS.

Hindi 500 essential A1–A2 words — Devanagari, IAST, IPA, gender, three-form verbs, audio TTS.

Indonesian 500 essential A1–A2 words — KBBI spelling + Jakarta IPA + audio TTS. No tones, no conjugation.

Italian 500 essential words (A1-A2 Plida) with IPA, gender, full verb conjugation, audio TTS.

Japanese 500 essential words covering JLPT N5 and N4, with kana, romaji, kanji and audio TTS.

Korean 500 essential words spanning TOPIK I and TOPIK II — start speaking Korean today with Hangul, romanization, audio TTS, and full verb conjugations.

Portuguese 500 essential words — A1 to A2 Brazilian Portuguese, with IPA, gender, conjugation, audio TTS.

Russian 500 essential words covering the full TORFL A1-A2 syllabus, with Cyrillic, stress marks, BGN/PCGN romanization, gender, full verb conjugation, and audio TTS.

Spanish 500 essential A1–A2 words — start speaking Spanish today, with pronunciation, example sentences, verb conjugations and audio TTS.

Thai 500 essential A1–A2 words — Thai script + RTGS + IPA + 5 tones + audio TTS.

Turkish 500 essential A1–A2 words — Istanbul standard + IPA + vowel harmony + audio TTS.

Vietnamese 500 essential A1–A2 words — chữ Quốc ngữ + IPA + 6 tones + audio TTS.

Headline analyzer — score your title's clickability, SEO length, emotional words, power words.

Slogan generator — 30+ proven copywriting formulas, generate brand slogans in seconds, bilingual.

Hashtag generator — Instagram / TikTok / Twitter / Xiaohongshu / Weibo hashtags from your topic.

Cover letter generator — fill 6 fields, pick a tone, get a tailored cover letter in 4 templates, bilingual.

Resume template builder — fill a form, get a clean PDF resume in 3 templates (modern / classic / minimal), bilingual.

Interview questions bank — 300+ real questions across behavioral / technical / case / culture, with strong answer frameworks.

200+ prompt templates for ChatGPT, Claude, Gemini — copy-paste, browse by use case.

Turn role, task, constraints, and output rules into a structured system prompt you can copy.

Generate eval cases, pass criteria, and edge cases from an AI feature, risks, and user path.

AI model comparison — 20+ models (GPT / Claude / Gemini / Llama / Qwen) across price, context, speed, capabilities (2026).

AI token counter — estimate token count for GPT / Claude / Gemini, with per-model cost calculator (2026 pricing).

Generate a prioritized content refresh checklist from URL, topic, and performance signals.

Generate SEO meta description options from a page topic, keywords, and audience.

Score a YouTube title for clarity, specificity, length, and keyword position.

Weekly report generator — fill blanks, get clean markdown, no AI hallucination.

Random names from 11 cultures — Chinese, English, Japanese, Korean, Arabic, Russian + 5 European.

Classic Lorem Ipsum filler text — paragraphs, sentences, or words — copy in one click, browser-only

Compare two blocks of text — line-by-line additions, deletions, equal — colour highlighted, browser-only

Remove duplicate lines from any list — case-sensitive optional, whitespace-trim optional, count duplicates — browser-only

Sort lines alphabetically, numerically, by length, or reverse — case-sensitive optional — browser-only

Count words, characters, sentences, paragraphs and reading time in any text — instant, browser-only

Convert text between camelCase, snake_case, kebab-case, PascalCase, Title Case, UPPER, lower — instant, browser-only

Test JavaScript regex live — match highlighting, group capture, replace preview, flag toggles — browser-only

Turn any title into a clean URL slug — lowercase, dashes, ASCII-safe transliteration, multiline batch — browser-only

Validate emails — RFC 5321 syntax + bulk paste + disposable detection + MX hint.

ROT13 / ROT47 / Caesar cipher — encode and decode in your browser, instant.

Text to binary (and back) — UTF-8 aware, 8/16/32 bit grouping, emoji safe.

Text to Morse code and back — encode, decode, audio playback, ITU standard.

Encode/decode HTML entities — & < > " ' and all numeric refs — browser-only

Convert Markdown to clean HTML — headings, lists, code, links, images, tables — instant live preview, browser-only

Markdown editor with live split-pane preview — GFM tables, fenced code with syntax highlight, math, emoji, table of contents, export as HTML / PDF-ready.

Build Markdown tables visually — add/remove rows, column alignment, paste from Excel / CSV — browser-only

Image to ASCII art — convert any image to text-based art with adjustable density and character set.

Generate ASCII art from text — figlet-style banners, multiple fonts.

Clean noisy logs by removing timestamps, ANSI colors, blank lines, long lines, or non-error entries in your browser.

Validate JSONL line by line, pretty-print it, convert to a JSON array, or export a CSV-like table locally.

JSONPath / JMESPath query tester — paste JSON, write a path, see matched values + matched paths highlighted live.

Paste JSON or NDJSON samples and infer a Draft 2020-12 style schema with types, required fields, formats, enums, and examples.

GraphQL formatter + minifier — beautify query/mutation/subscription/schema, validate syntax, copy minified single-line for HTTP body.

.env file validator — parse Bash-style .env, detect dups / missing required / unsafe values / leaked secret patterns; cross-compare prod / staging / dev envs.

Scan .env files, config snippets, and CI logs locally for likely API keys, tokens, private keys, JWTs, and database URLs.

LaTeX equation editor live — type/paste LaTeX, see math rendered live via MathJax 3 (CDN), copy as SVG/PNG/Markdown/MathML, 30+ symbol palette.

Kanji + Chinese character stroke order viewer — animated SVG showing correct stroke sequence + direction, with romaji/pinyin/meaning, 500+ common characters.

Paste logs and group repeated errors, warnings, stack traces, HTTP statuses, endpoint patterns, and time ranges into a local incident report.

Extract, dedupe, and export email addresses from pasted text or uploaded local files.

Validate and explain issues in email addresses from pasted text or uploaded local files.

Normalize, sort, and prepare email addresses from pasted text or uploaded local files.

Find duplicates and keep one clean copy of email addresses from pasted text or uploaded local files.

Convert email addresses from pasted text or uploaded local files.

Extract, dedupe, and export urls from pasted text or uploaded local files.

Validate and explain issues in urls from pasted text or uploaded local files.

Normalize, sort, and prepare urls from pasted text or uploaded local files.

Find duplicates and keep one clean copy of urls from pasted text or uploaded local files.

Convert urls from pasted text or uploaded local files.

Extract, dedupe, and export domain names from pasted text or uploaded local files.

Validate and explain issues in domain names from pasted text or uploaded local files.

Normalize, sort, and prepare domain names from pasted text or uploaded local files.

Find duplicates and keep one clean copy of domain names from pasted text or uploaded local files.

Convert domain names from pasted text or uploaded local files.

Extract, dedupe, and export ipv4 addresses from pasted text or uploaded local files.

Validate and explain issues in ipv4 addresses from pasted text or uploaded local files.

Normalize, sort, and prepare ipv4 addresses from pasted text or uploaded local files.

Find duplicates and keep one clean copy of ipv4 addresses from pasted text or uploaded local files.

Convert ipv4 addresses from pasted text or uploaded local files.

Extract, dedupe, and export ipv6 addresses from pasted text or uploaded local files.

Validate and explain issues in ipv6 addresses from pasted text or uploaded local files.

Normalize, sort, and prepare ipv6 addresses from pasted text or uploaded local files.

Find duplicates and keep one clean copy of ipv6 addresses from pasted text or uploaded local files.

Convert ipv6 addresses from pasted text or uploaded local files.

Extract, dedupe, and export uuids from pasted text or uploaded local files.

Validate and explain issues in uuids from pasted text or uploaded local files.

Normalize, sort, and prepare uuids from pasted text or uploaded local files.

Find duplicates and keep one clean copy of uuids from pasted text or uploaded local files.

Convert uuids from pasted text or uploaded local files.

Extract, dedupe, and export hashtags from pasted text or uploaded local files.

Validate and explain issues in hashtags from pasted text or uploaded local files.

Normalize, sort, and prepare hashtags from pasted text or uploaded local files.

Find duplicates and keep one clean copy of hashtags from pasted text or uploaded local files.

Convert hashtags from pasted text or uploaded local files.

Extract, dedupe, and export social handles from pasted text or uploaded local files.

Validate and explain issues in social handles from pasted text or uploaded local files.

Normalize, sort, and prepare social handles from pasted text or uploaded local files.

Find duplicates and keep one clean copy of social handles from pasted text or uploaded local files.

Convert social handles from pasted text or uploaded local files.

Extract, dedupe, and export phone numbers from pasted text or uploaded local files.

Validate and explain issues in phone numbers from pasted text or uploaded local files.

Normalize, sort, and prepare phone numbers from pasted text or uploaded local files.

Find duplicates and keep one clean copy of phone numbers from pasted text or uploaded local files.

Convert phone numbers from pasted text or uploaded local files.

Extract, dedupe, and export postal codes from pasted text or uploaded local files.

Validate and explain issues in postal codes from pasted text or uploaded local files.

Normalize, sort, and prepare postal codes from pasted text or uploaded local files.

Find duplicates and keep one clean copy of postal codes from pasted text or uploaded local files.

Convert postal codes from pasted text or uploaded local files.

Extract, dedupe, and export credit card numbers from pasted text or uploaded local files.

Validate and explain issues in credit card numbers from pasted text or uploaded local files.

Normalize, sort, and prepare credit card numbers from pasted text or uploaded local files.

Find duplicates and keep one clean copy of credit card numbers from pasted text or uploaded local files.

Convert credit card numbers from pasted text or uploaded local files.

Extract, dedupe, and export hex colors from pasted text or uploaded local files.

Validate and explain issues in hex colors from pasted text or uploaded local files.

Normalize, sort, and prepare hex colors from pasted text or uploaded local files.

Find duplicates and keep one clean copy of hex colors from pasted text or uploaded local files.

Convert hex colors from pasted text or uploaded local files.

Extract, dedupe, and export css variables from pasted text or uploaded local files.

Validate and explain issues in css variables from pasted text or uploaded local files.

Normalize, sort, and prepare css variables from pasted text or uploaded local files.

Find duplicates and keep one clean copy of css variables from pasted text or uploaded local files.

Convert css variables from pasted text or uploaded local files.

Extract, dedupe, and export environment variables from pasted text or uploaded local files.

Validate and explain issues in environment variables from pasted text or uploaded local files.

Normalize, sort, and prepare environment variables from pasted text or uploaded local files.

Find duplicates and keep one clean copy of environment variables from pasted text or uploaded local files.

Convert environment variables from pasted text or uploaded local files.

Extract, dedupe, and export http headers from pasted text or uploaded local files.

Validate and explain issues in http headers from pasted text or uploaded local files.

Normalize, sort, and prepare http headers from pasted text or uploaded local files.

Find duplicates and keep one clean copy of http headers from pasted text or uploaded local files.

Convert http headers from pasted text or uploaded local files.

Extract, dedupe, and export jwt tokens from pasted text or uploaded local files.

Validate and explain issues in jwt tokens from pasted text or uploaded local files.

Normalize, sort, and prepare jwt tokens from pasted text or uploaded local files.

Find duplicates and keep one clean copy of jwt tokens from pasted text or uploaded local files.

Convert jwt tokens from pasted text or uploaded local files.

Extract, dedupe, and export base64 blocks from pasted text or uploaded local files.

Validate and explain issues in base64 blocks from pasted text or uploaded local files.

Normalize, sort, and prepare base64 blocks from pasted text or uploaded local files.

Find duplicates and keep one clean copy of base64 blocks from pasted text or uploaded local files.

Convert base64 blocks from pasted text or uploaded local files.

Extract, dedupe, and export iso dates from pasted text or uploaded local files.

Validate and explain issues in iso dates from pasted text or uploaded local files.

Normalize, sort, and prepare iso dates from pasted text or uploaded local files.

Find duplicates and keep one clean copy of iso dates from pasted text or uploaded local files.

Convert iso dates from pasted text or uploaded local files.

Extract, dedupe, and export semantic versions from pasted text or uploaded local files.

Validate and explain issues in semantic versions from pasted text or uploaded local files.

Normalize, sort, and prepare semantic versions from pasted text or uploaded local files.

Find duplicates and keep one clean copy of semantic versions from pasted text or uploaded local files.

Convert semantic versions from pasted text or uploaded local files.

Extract, dedupe, and export mac addresses from pasted text or uploaded local files.

Validate and explain issues in mac addresses from pasted text or uploaded local files.

Normalize, sort, and prepare mac addresses from pasted text or uploaded local files.

Find duplicates and keep one clean copy of mac addresses from pasted text or uploaded local files.

Convert mac addresses from pasted text or uploaded local files.

Extract, dedupe, and export dois from pasted text or uploaded local files.

Validate and explain issues in dois from pasted text or uploaded local files.

Normalize, sort, and prepare dois from pasted text or uploaded local files.

Find duplicates and keep one clean copy of dois from pasted text or uploaded local files.

Convert dois from pasted text or uploaded local files.

Cat breed finder — answer 10 lifestyle questions, get 5 matching cat breeds with personality, grooming needs, friendliness.

Dog breed finder — answer 10 questions about your lifestyle, get 5 matching breeds with size, temperament, exercise needs.

Dream dictionary — search dream symbols and meanings (Chinese 周公解梦 + Jungian).

Palmistry guide — 6 major lines + 7 mounts explained with diagrams, traditional readings, bilingual.

200+ meridian acupoints / WHO 2008 standard locations / with contraindications, manipulation, and combinations.

Yoga pose library — 60+ asanas with Sanskrit + Chinese + English names, benefits, contraindications, modifications.

Unicode 15.1 / 1500+ emojis with bilingual search — one-click copy, browser-only

Emoji recommender — paste your headline or post, get matching emoji suggestions.

Daily fortune cookie — bilingual fortunes plus lucky numbers, lucky color, daily affirmation. 365 unique reads.

MBTI quick test — 28 questions, 5 minutes, get your 4-letter type with detailed reading.

College major matcher — Holland code (RIASEC) test, 40 questions, recommend 10+ matching majors with career path.

awk + sed cheat sheet — 80+ one-liners for text processing, with real examples and common pitfalls.

AWS CLI cheat sheet — 80+ commands for EC2 / S3 / IAM / Lambda / RDS / EKS / CloudFormation with real examples.

Bash cheat sheet — 100+ commands & idioms for variables, conditionals, loops, functions, pipes, traps, with real one-liners.

curl cheat sheet — 80+ curl commands for GET/POST/auth/upload/download/SSL/proxy, with real examples and pitfalls.

DNS record explainer — all 18 common record types (A, AAAA, CNAME, MX, TXT, SRV, etc.) with syntax, examples, and gotchas.

Docker command cheat sheet — 80+ commands with real examples, common mistakes, and Compose section.

Elasticsearch cheat sheet — 80+ Query DSL, mapping, analyzer, aggregation, replication, with real examples.

Git command cheat sheet — searchable, with explanations, common mistakes, and real examples.

Go (Golang) cheat sheet — 100+ idiomatic snippets covering syntax, goroutines, channels, generics, errors, stdlib.

HTTP status code explorer — all 70+ codes with meaning, common causes, real examples, and what to check.

kubectl cheat sheet — 100+ Kubernetes commands with real examples, common pitfalls, and YAML snippets.

Markdown syntax cheat sheet — every rule with live preview side by side, GFM + flavors.

MongoDB cheat sheet — 80+ shell commands & query operators for CRUD, aggregation, indexing, replication.