Period Tracker
Track cycles and estimate ovulation & fertile window (local-only, informational).
What is Period Tracker
Estimate your cycle in three fields: enter the first day of your last period, your average cycle length and period duration, and get your current phase, the predicted next period, ovulation day and fertile window. Everything is computed locally. Sign-in required. For reference only — not a substitute for medical advice.
How to use Period Tracker
- Enter the first day of your last period, average cycle length and duration
- Press calculate to see your current phase and the three predicted dates
- Plan travel or conception around the forecast
Frequently asked questions
How is ovulation estimated?
By the standard mid-cycle approximation: about 14 days before the predicted next period, with the fertile window spanning the days around it. Real ovulation varies cycle to cycle.
Can I rely on it for contraception or conception timing?
No — cycle predictions are statistical estimates, not a contraceptive method. Irregular cycles make them less reliable; consult a doctor for family-planning decisions.
Is my cycle data stored or uploaded?
The calculation itself runs locally in your browser; no readings are sent to a server.
Is Period Tracker free?
Period Tracker is completely free — open the page and use every feature with no hidden charges.
Do I need to download or install Period Tracker?
No download or installation is needed. It is an online tool that runs in the browser on your phone, tablet and computer.
Do I need an account to use Period Tracker?
No. Use the tool right away — no account or sign-in required.
Does Period Tracker work on mobile?
Yes. The page is fully responsive and works on phones, tablets and desktop browsers.