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Ovulation Calculator
Find your fertile window.
Estimate ovulation day and fertile window from your last period. Free, no signup.
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.