Ovulation Calculator

Free ovulation calculator. Enter your last period date and cycle length to predict your fertile window, ovulation day and next period.

First day of last period

Average cycle length (days)

Good to know

Ovulation Calculator — frequently asked questions

When am I most fertile?

Your fertile window is typically the five days before ovulation plus ovulation day itself. Ovulation usually occurs about 14 days before your next period.

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