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Ovulation & Fertility Tracker — 6-Month Fertile Window Planner with BBT Logging

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

  • Runs locally
  • Category Calculator
  • Best for Getting a realistic range before a purchase, plan, workout, or schedule decision.
For trying-to-conceive (TTC) reference — read this first
This planner predicts fertile windows so you can time intercourse for conception. It is NOT a contraceptive — the calendar method has roughly a 1-in-4 failure rate per year. If you have been trying for over 12 months (or 6 months if you are over 35), or if your cycles vary by more than 7 days, please see an OB-GYN or a reproductive endocrinologist. Nothing here replaces medical advice.
6-month conception plan
CycleOvulationFertile windowBest conception daysNext period
Cycle 12026-07-162026-07-11 → 2026-07-172026-07-14 · 2026-07-152026-07-30
Cycle 22026-08-132026-08-08 → 2026-08-142026-08-11 · 2026-08-122026-08-27
Cycle 32026-09-102026-09-05 → 2026-09-112026-09-08 · 2026-09-092026-09-24
Cycle 42026-10-082026-10-03 → 2026-10-092026-10-06 · 2026-10-072026-10-22
Cycle 52026-11-052026-10-31 → 2026-11-062026-11-03 · 2026-11-042026-11-19
Cycle 62026-12-032026-11-28 → 2026-12-042026-12-01 · 2026-12-022026-12-17
Basal body temperature (BBT) log

Take your temperature first thing in the morning, before sitting up. Add each reading below — the chart will draw a 6-day baseline and flag the biphasic shift that confirms ovulation already happened.

No readings yet. Add at least 9 days of morning temperatures to detect the ovulation shift.
Your privacy
All math runs locally in your browser. The dates and temperatures you enter are never uploaded, never logged, never sent anywhere.

What this tool does

Free online ovulation and fertility tracker built for couples who are trying to conceive (TTC). Enter the first day of your last period, your typical cycle length (21–35 days, default 28), and your luteal phase length (10–16 days, default 14) and get a 6-month conception plan in a single table: the exact ovulation day, the 7-day fertile window (5 days before ovulation through 1 day after — the span sperm and egg can actually meet), the two highest-probability days for timed intercourse (ovulation minus 2 and minus 1, when sperm is already waiting in the reproductive tract), and the predicted start of every upcoming period. A built-in basal body temperature (BBT) logger lets you record morning readings, draws a 6-day baseline, and flags the classical biphasic shift (three consecutive days at or above baseline + 0.3 °C) — the after-the-fact confirmation that ovulation already happened. All math runs locally in your browser: dates and temperatures are never uploaded, never logged, never sent anywhere. This is a TTC reference, not contraception — the calendar method has roughly a 1-in-4 yearly failure rate. If you have been trying for over 12 months (or 6 months over age 35), see an OB-GYN or reproductive endocrinologist.

Tool details

Input
Numbers
The page exposes text boxes, numeric controls, file pickers, or structured inputs depending on the tool.
Output
Live result + Copy + Preview
The result area focuses on usable output, with copy, download, or preview actions when supported.
Privacy
Browser-side processing
The main tool logic does not call an external API, so inputs normally stay in the current tab.
Save / share
No account required
Open the page and use it; whether results survive refresh depends on the tool.
Performance budget
Initial JS <= 22 KB
No WASM budget is declared, keeping the tool quick to open on mobile.
Best fit
Calculator · Content Creator
Category and role tags drive related tools, internal links, and quick fit checks.

How to use

  1. 1. Input

    Paste or drop your content into the tool panel.

  2. 2. Process

    Click the button. All processing is local in your browser.

  3. 3. Copy / Download

    Copy the result or download to disk in one click.

How Ovulation & Fertility Tracker fits into your work

Use it for fast estimates, comparisons, and planning numbers before you make the final call.

Calculation jobs

  • Getting a realistic range before a purchase, plan, workout, or schedule decision.
  • Comparing scenarios by changing one input at a time.
  • Turning rough assumptions into a number you can discuss.

Calculation checks

  • Double-check units, dates, rates, and rounding assumptions.
  • Treat health, finance, tax, and legal outputs as planning aids, not professional advice.
  • Save the inputs that produced an important result so you can reproduce it later.

Good next steps

These links move the current task into a more complete workflow.

  1. 1 BMI Calculator Body Mass Index calculator with WHO + Asian classifications — metric and imperial — browser-only Open
  2. 2 Safe Period & Ovulation Calculator Period & ovulation calculator — predict next period, fertile window, safe days (based on calendar method). Open
  3. 3 Pregnancy Due Date Calculator Pregnancy due date calculator — track weeks, trimester, baby development by week. Open

Real-world use cases

  • First TTC cycle, building a 6-month plan from scratch

    You just stopped birth control and your last period started May 12, cycles run about 30 days, luteal phase unknown. Enter those numbers (default luteal 14) and the table shows ovulation near May 28, fertile window May 23 to May 29, and the two priority days May 26 and May 27. You bookmark the share link so your partner sees the same two dates without a back-and-forth.

  • Irregular cycle, re-anchoring after every period

    Your cycles swing between 26 and 34 days, so a fixed calendar guess is useless past the first month. You treat only cycle 1 as firm, then the moment a new period actually starts you come back and re-enter that date as the new LMP. Over three cycles you notice ovulation lands day 18 to day 22, narrowing where to start watching cervical mucus and LH sticks.

  • Confirming ovulation with the BBT logger

    You take your temperature at 6:30 a.m. before getting up and log it daily. After two weeks the logger draws the 6-day baseline and flags a 3-day shift starting March 14 (36.4, then 36.7, 36.8, 36.8). That biphasic jump confirms you ovulated around March 13, and the gap to your next period tells you your real luteal phase is 12 days, not the default 14.

  • Nailing down your personal luteal phase

    After charting BBT for three months you see your temperature rises and your period arrives 11 days later every time. You change the luteal-phase field from 14 to 11. The predicted ovulation day moves three days earlier, which shifts your two priority intercourse days too. The plan now matches your body instead of a textbook average, sharpening every future month.

Common pitfalls

  • Treating month 5 or 6 as exact. Cycles drift a few days, so only the first cycle is firm. Re-enter your real LMP each new period; otherwise May becomes off by a week by October.

  • Timing intercourse for the ovulation day only. The egg lives 12 to 24 hours, so peak odds are ovulation minus 2 and minus 1, when sperm is already waiting. Start before ovulation, not on it.

  • Using BBT to predict tomorrow. The temperature rise confirms ovulation already happened, it does not forecast it. Use BBT to learn your luteal phase, and LH sticks or mucus to catch the surge ahead.

Privacy

Every date and temperature you enter is computed in your browser and stays there. Nothing is uploaded, logged, or sent to a server, and your readings are not written into the page URL, so a share link carries no menstrual or fertility data. Open the network tab while you add a reading and you will see no request leave the page. After the page loads once, the tool keeps working offline.

FAQ

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Made by Toolora · 100% client-side · Updated 2026-07-02