Baby Tools › Ovulation Calculator

Ovulation Calculator

Find your fertile window and the best days to try to conceive.

This tool is for general information only and is not medical advice. Always talk to your doctor or midwife about your pregnancy and your baby.

How it works

1Enter the first day of your last period.

2Add your average cycle length.

3See your fertile window and ovulation day.

When am I most fertile?

Your fertile window is the ~6 days ending on ovulation day. The two days before ovulation are usually the most fertile.

When does ovulation happen?

Ovulation typically happens about 14 days before your next period — so it depends on your cycle length, not just day 14.