Free calculator

Fertility window calculator

See your fertile days based on an ovulation estimate.

Estimate, not a diagnosis. This tool gives an educational estimate based on the numbers you enter. It cannot account for your individual health history — consult a healthcare professional for anything clinical.

Estimated ovulation date

July 2026

SMTWTFS

Details

The fertile window represents the days when intercourse is most likely to lead to conception, because sperm can survive several days and the egg is viable for roughly 24 hours after ovulation.

Limitations

This is an estimate, not a contraceptive method. Ovulation timing varies between cycles — do not rely on this alone to avoid or achieve pregnancy.