Ovulation Calculator

Find your fertile window and most likely ovulation date.

Estimated Ovulation Date
Your fertile window (6 days)
Next period expected
Days until ovulation

How ovulation is calculated

Ovulation typically occurs 14 days before the next expected period. For a 28-day cycle that means day 14. For longer or shorter cycles, this shifts accordingly.

The fertile window

Sperm can survive in the reproductive tract for up to 5 days. An egg lives roughly 24 hours after release. Combined, your fertile window spans about 6 days: the 5 days before ovulation and the day of ovulation itself.

Important to know

Cycle lengths vary month to month. This calculator provides an estimate based on average cycle length and is most useful for people with regular cycles.

This calculator is for general informational purposes only. It is not a substitute for professional medical advice.