Ovulation Calculator
Find your most fertile days and ovulation date from your last period and cycle length.
How it works
Ovulation usually happens about 14 days before your next period. From your last period and cycle length, this tool estimates your ovulation day and your fertile window — the ~6 days when conception is most likely. It's an estimate, not a contraceptive method.
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Frequently asked questions
When am I most fertile?
Your most fertile days are the day of ovulation and the 5 days before it — that's the fertile window this calculator shows.
Is this reliable for avoiding pregnancy?
No. It's an estimate based on average cycles and should not be used as a contraceptive method. Ovulation can vary from cycle to cycle.