Calculator for Teacher
46 calculator tools hand-picked for Teacher.
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24-Point Solver & Game
24-point solver and game — enter 4 numbers and get every solution instantly, or play random hands against the clock.
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Age Calculator
Calculate your exact age — years, months, days, hours. Compare two dates or count to a future date.
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Number Base Converter
Number base converter — binary, octal, decimal, hex, and any base 2-36. Bitwise too.
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Birthday Paradox Calculator
Birthday paradox calculator — see the probability of shared birthdays in a group of N people, visualized step by step.
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Chemistry Equation Balancer
Chemistry equation balancer — paste an unbalanced equation, solve coefficients using the matrix method, show step-by-step.
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Chinese Numeric Converter
Arabic ⇄ Chinese number — simple (一二三), formal (壹貳參), or amount (金额大写 with 元角分).
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Chinese Stroke Counter
Chinese character stroke counter — count strokes for any hanzi, traditional or simplified.
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Chinese Zodiac Sign Checker (Sheng Xiao)
Chinese zodiac checker — your animal sign, element, compatibility, lucky numbers/colors by birth year.
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College Major Matcher (Holland RIASEC, 40 Questions)
College major matcher — Holland code (RIASEC) test, 40 questions, recommend 10+ matching majors with career path.
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Complex Number Calculator
Complex number calculator — +-×÷ + conjugate + modulus + argument + polar/Cartesian conversion + powers + roots + Euler form, complex plane visualization.
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Countdown Timer
Countdown timer — to any date and event, with live ticking down to seconds.
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Density Calculator
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
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Derivative Calculator (Step-by-Step)
Derivative calculator with step-by-step — symbolic differentiation, chain/product/quotient rule shown, plot f(x) and f'(x).
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Final Grade Calculator
Current grade + final weight + target → exactly what you need on the final — browser-only
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Fraction Calculator
Add, subtract, multiply, divide fractions — auto-reduced, with steps, mixed ⇄ improper ⇄ decimal — browser-only
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GCD & LCM Calculator
GCD + LCM of any list of integers — Euclidean steps, prime factorization, prime-factor table — exact BigInt math, browser-only
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GPA Calculator
Weighted GPA from courses + credits + grades — US 4.0 / 4.3 and China 4.0 / 4.5 conversion, letter ⇄ percentage ⇄ point — browser-only
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Grade Calculator
Weighted course grade + what you need on the final — multi-row categories, letter grade, shareable link — browser-only
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Half-Life Calculator
Solve any radioactive-decay unknown — initial amount, remaining amount, elapsed time, or half-life — with exact exponential math, all in your browser
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Ideal Gas Law Calculator
Solve PV = nRT for pressure, volume, amount, or temperature — pick any unknown, mix any units, runs in your browser
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IELTS Band Calculator
IELTS band calculator — convert listening/reading raw scores to band, average four skills, see your overall band.
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Integral Calculator (Step-by-Step)
Indefinite integral calculator step-by-step — symbolic integration, substitution + integration by parts shown, plot f(x) and F(x).
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Kids Allowance Calculator
Kids allowance calculator — age-appropriate weekly/monthly amount with chore-based breakdown, savings goal sandbox.
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Lunar Calendar Converter (Chinese Nongli)
Gregorian ⇄ Chinese Lunar (Nongli) calendar — bi-directional, accurate 1900-2100.
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Math Formula Reference
Math formula reference — algebra, geometry, trigonometry, calculus, statistics, all in one place.
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Matrix Calculator
Matrix calculator — add/sub/multiply/inverse/determinant/transpose/rank/RREF/eigenvalues for n×m matrices, step-by-step.
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Molar Mass Calculator
Type any chemical formula — get molar mass, a per-element mass-percent table, and mass↔mole conversion. IUPAC weights, browser-only.
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Percent Error Calculator
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.
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Periodic Table
Interactive periodic table — 118 elements, properties, electron config, search.
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Probability Distribution Visualizer
Probability distribution visualizer — normal/t/chi-sq/F/binomial/poisson/exp/uniform PDF+CDF, P(a≤X≤b) area, z/p table replacement.
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Projectile Motion Calculator
Solve flight time, max height, range & impact speed from launch speed, angle and height — with a live trajectory plot, browser-only
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Pythagorean Theorem Calculator
Solve a²+b²=c² — find the hypotenuse, find a missing leg, or measure the distance between two points (2D & 3D). Browser-only.
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Quadratic Equation Solver
Quadratic equation solver — ax² + bx + c = 0, discriminant analysis, real + complex roots, vertex/intercepts, parabola visualization.
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Roman Numeral Converter
Arabic ⇄ Roman, both directions, live — strict validation, step-by-step breakdown, vinculum up to 3,999,999 — 100% browser-only
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Scientific Calculator
Scientific calculator — sin / cos / log / sqrt / power, with full keyboard input + history, deg/rad mode.
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Screen Time Budget
Screen time budget — track and visualize daily screen time across phone/tablet/PC, with age-based recommendations from WHO/AAP.
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Significant Figures Calculator
Count sig figs · round to N significant figures · do sig-fig arithmetic — exact string-level math, browser-only
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Statistics Basic Calculator
Basic statistics calculator — mean/median/mode/variance/std-dev/quartiles/range/IQR/skewness/kurtosis + histogram + box plot, paste any numbers.
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Sudoku Generator
Sudoku generator and solver — 4 difficulties (easy / medium / hard / expert), unique-solution guaranteed, play in the browser or print as PDF.
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Test Grade Calculator
Answers wrong → percent + letter grade + a full printable grading chart — the teacher's EZ Grader, browser-only
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Triangle Calculator
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.
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Trigonometry Calculator
Trigonometry calculator — sin/cos/tan + inverse + sec/csc/cot, degree/radian/gradient, unit circle visualization, exact values.
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Typing Speed Test
Typing speed test — WPM, accuracy, real-time mistakes, English + Chinese pinyin modes.
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Wavelength Frequency Calculator
Convert between wavelength λ, frequency f, and photon energy E · c = λf · E = hf · spectrum band + visible colour · browser-only
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Weighted Grade Calculator
Items + weights → your current course grade, with letter and banked points — browser-only
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Z-Score Calculator
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