Ovulation calculator

Enter the first day of your last period and your usual cycle length. We estimate ovulation about 14 days before your next period and show the days when pregnancy is most likely.

How it works

An egg lives for about 12 to 24 hours after ovulation, while sperm can survive for up to 5 days. That is why the fertile window covers the 5 days before ovulation and the day of ovulation. Cycles vary from month to month, so treat these dates as an estimate. Ovulation tests and tracking cervical mucus or basal body temperature can help you narrow it down.

This calculator gives an estimate only. If you have irregular cycles or have been trying to conceive for a year (6 months if you are over 35), talk to a doctor.