πΈ Period & Ovulation Calculator
Predict your next period, ovulation, and fertile days β private, no data stored, 100% clientβside.
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Next period
π₯ Ovulation date
π Fertile window
π No signup
The first day you started bleeding
Usually 21β35 days
How many days bleeding lasts
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Next period starts
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π₯ Ovulation day
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π Fertile window (most fertile days)
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Based on average cycle. Sperm can live up to 5 days.
π Cycle summary
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β οΈ Medical Disclaimer
This calculator provides estimates based on average cycle data and is for educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. If you have irregular cycles or health concerns, please consult a healthcare provider.
This calculator provides estimates based on average cycle data and is for educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. If you have irregular cycles or health concerns, please consult a healthcare provider.
πΈ How the Period Calculator Works
This tool uses the standard calendar method to estimate your next period and fertile days based on your average cycle length. It works entirely in your browser β no data is stored or sent anywhere.
- Next period = Last period date + cycle length
- Ovulation = Next period date β 14 days (typical luteal phase)
- Fertile window = Ovulation day β 5 days to ovulation day + 1 day
For irregular cycles, results may vary. Track your cycles over time for better predictions.
β¨ Why Choose Our Calculator?
- β 100% private β no signup, no data storage, no tracking
- β Clientβside β everything runs in your browser
- β Adjustable cycle length & period duration β personalized results
- β Clear fertile window β know your most fertile days
- β Free forever β no hidden costs
π‘ Understanding Your Cycle
A typical menstrual cycle lasts 28 days, but cycles from 21 to 35 days are normal. Ovulation usually occurs 14 days before your next period. The fertile window includes the 5 days before ovulation and the day of ovulation because sperm can live for up to 5 days.
β Frequently Asked Questions
It's accurate for women with regular cycles (length variation within a few days). For irregular cycles, predictions are estimates. The best way to improve accuracy is to track your cycles over several months and adjust the average cycle length accordingly.
Absolutely. This tool does not store any information. All calculations happen locally in your browser. No cookies, no tracking, no signup. Your cycle data never leaves your device.
No. This tool is for educational purposes only. It should not be used as a form of contraception. Please consult a healthcare provider for family planning advice.