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Ovulation Calculator
Find your fertile window.
Estimate ovulation day and fertile window from your last period. Free, no signup.
Please note: This calculator gives a general estimate for information only. Cycles and pregnancies vary from person to person, so real dates can be different. It is not medical advice. Please see a doctor or midwife for advice about your own situation.
Frequently Asked Questions
Ovulation typically occurs 14 days before your next period starts, so it's estimated as your cycle length minus 14 days from the first day of your last period.
The 5 days before ovulation plus the day after, since sperm can survive several days and the egg is viable for about 24 hours after release.