Period Tracker

What is Period Tracker?

Period Tracker helps you monitor your menstrual cycle privately. Log your period dates, track cycle patterns, and get predictions for your next period and fertile window — all data stays on your device with no account required.

The tracker takes a moving average of your last few cycles to predict the next period, fertile window, and ovulation day. You can log flow intensity (light, medium, or heavy), separate spotting from a real period start, tag symptoms such as cramps or mood swings, mark a mood, rate your energy level and sleep quality, and add private notes per cycle. Once you have three or more periods logged, a statistics panel shows your shortest, longest, and average cycle length so you can spot irregularity at a glance. Everything stays on your device — no account, no upload, no sync.

How to use

1. Enter the start date of your last period and your average cycle length to begin tracking.
2. Log each period as it occurs to improve prediction accuracy over time.
3. View your cycle calendar with predicted period dates, fertile windows, and ovulation estimates.

When to use

• You want a private record of your cycle without trusting a phone app with health data.
• You're trying to conceive and need to know when ovulation and the fertile window fall.
• You're spotting irregular patterns to discuss with a gynaecologist at the next visit.

Result

You want to track your cycle without signing up for apps that sell health data. Enter your last period date (March 15) and cycle length (28 days) — the tracker predicts your next period around April 12 and shows your fertile window, all stored locally.

FAQ

How accurate are the period predictions for irregular cycles?

Predictions are based on a simple average of your logged cycle lengths, so accuracy improves after 3 or 4 logged periods. For cycles that vary by more than 7 days, treat the predicted date as a window, not a fixed day.

Where is my data stored?

Your cycle history, symptoms, and notes are saved locally on your device. Nothing is sent to a server, there is no account, and clearing this site's local data will erase the log. If you switch devices the log does not follow — use the CSV or PDF export to take it with you.

How is the fertile window calculated?

The fertile window is estimated as roughly 5 days before ovulation through the day of ovulation, which itself is placed about 14 days before the next predicted period. This is a textbook estimate and won't reflect hormonal conditions like PCOS.

Can I export my cycle log for a doctor's appointment?

Yes. The Export menu offers CSV (opens in Excel or Sheets) and PDF. The PDF lists each cycle with start date, length, flow level, and any symptoms or notes you logged, which is useful when discussing patterns with a healthcare provider.

Will this tool work for tracking after stopping birth control?

It works as a log, but predictions may be unreliable for the first 3 to 6 months after stopping hormonal contraception while your cycle stabilises. Focus on recording dates and symptoms in that period rather than the predicted next date.

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