Ovulation Calculator
Find your fertile window and most likely ovulation day based on your cycle.
About Ovulation
How long is the fertile window?
The fertile window is typically 6 days — the 5 days before ovulation and the day of ovulation itself. Sperm can survive in the reproductive tract for up to 5 days, making conception possible in the days before ovulation.
How accurate is this calculator?
This is an estimate based on average cycle patterns. Actual ovulation can vary due to stress, illness, or cycle irregularities. For precise tracking, combine this with basal body temperature or LH ovulation tests.