Period Tracker
Newperiod tracker · menstrual cycle calculator · cycle tracking · period calendar · 생리주기 계산
Add a cycle record
Log at least 2 cycles to see your average and predictions.
June 2026
Records
No records yet. Add your first cycle above.
⚠️ Medical disclaimer
Predictions are estimates for reference only and cycles can vary. For contraception, pregnancy planning, or any health concern, consult a healthcare professional.
Do not use this tool as a method of birth control.
How to use
Log each cycle to predict your next period, ovulation and fertile window — privately, on your device.
- 1
Enter your period start date and how many days it lasted, then add the record.
- 2
Add a record each month — the more cycles you log, the better the average.
- 3
See your average cycle, next-period prediction (D-day), ovulation and fertile window.
- 4
Check the calendar and cycle-length chart; export your records to back them up.
FAQ
Is this tool free?
Yes — no sign-up, no installation, completely free to use right away.
What is this tool?
Period Tracker keeps a private log of your menstrual cycles and uses it to estimate your average cycle length, predict your next period (with a D-day countdown), and show an ovulation and fertile-window estimate on a monthly calendar. Add a record each month — start date, period length and an optional symptom note — and a cycle-length chart helps you see how regular your cycles are. Everything is stored only in your browser and never sent to a server; use Export/Import to back up your records or move them to another device. Predictions are estimates for reference only and cycles naturally vary — this tool is not a contraceptive method.
Are my records saved to a server?
No. Every record is stored only in your browser (local storage) and is never uploaded. Use Export to back them up to a file.
How accurate are the predictions?
They are estimates based on your average cycle length and are for reference only. Real cycles vary month to month, so treat the dates as approximate.
How is this different from an ovulation calculator?
An ovulation calculator gives a one-off estimate from a single date. Period Tracker keeps a running log of your cycles, learns your average, and tracks regularity over time on a calendar.
Can I use this for birth control?
No. Do not rely on these predictions for contraception or to plan or avoid pregnancy. For those decisions, consult a healthcare professional.