Ovulation Calculator

Why your ovulation date matters

In women with regular cycles, ovulation happens about 14 days before the next period starts. The fertile window is the 5 days before ovulation plus the day of ovulation itself - 6 days in total - because sperm can survive in the reproductive tract for 3 to 5 days.

Natural conception success rates

A healthy couple where the female partner is under 35 has roughly a 20-25% chance of conceiving in each cycle when intercourse is timed to the fertile window. If 12 months of trying (6 months if she is over 35) has not worked, it is worth seeing a fertility specialist.

Read more about natural conception

This calculator gives an estimate based on a regular cycle. It is not a substitute for medical advice, and it should not be used to avoid pregnancy.