Health
Period Calculator
Predict next periods, ovulation, and fertile window.
Inputs
Period Calculator
Result
Next period
Sun Aug 23 2026
- Following period
- Sun Sep 20 2026
- Third period
- Sun Oct 18 2026
- Next ovulation
- Sun Aug 09 2026
- Fertile window
- Tue Aug 04 2026 → Mon Aug 10 2026
How it's calculated
Next period = last + cycle. Ovulation = next period − 14 days. Fertile window = ovulation −5 to +1 days.
Common questions
Is this accurate for irregular cycles?
It assumes a consistent cycle length; if yours varies, treat these as rough estimates.
Can I use this for contraception?
No — it's an estimate, not a birth control method.
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