Period & Ovulation Calculator
Track your menstrual cycle, predict periods, ovulation dates, and fertile windows. Privacy-first — all calculations happen in your browser.
Period & Ovulation Calculator
Track your menstrual cycle, predict periods, fertile windows & ovulation days.
Your Cycle Details
Enter your last period date to see predictions
or click "Try Example" for a demo
How to Use Period & Ovulation Calculator
- 1
Enter the start date of your last menstrual period.
- 2
Set your average cycle length (default 28 days) and period duration (default 5 days).
- 3
Click "Calculate Cycle" to see predictions.
- 4
View the color-coded calendar, countdown cards, and upcoming cycles table.
- 5
Export your data as CSV or save to history for future reference.
About Period & Ovulation Calculator
Track and predict your menstrual cycle with our free Period & Ovulation Calculator. Enter your last period date, average cycle length, and period duration to get accurate predictions for upcoming periods, ovulation dates, and fertile windows.
Features a beautiful color-coded 2-month calendar showing period days, ovulation, fertile window, and luteal phase at a glance. Countdown cards show days until your next period, ovulation, and fertile window.
View up to 8 upcoming cycles in a detailed table with predicted start dates, end dates, ovulation dates, and fertile windows. Export your cycle data as CSV for personal records or to share with your healthcare provider.
100% privacy-first: All calculations happen entirely in your browser. No data is ever sent to any server. Your cycle history is stored only in your browser's localStorage on your device.