Ovulation Calculator
Estimate your fertile window and ovulation day from your cycle.
—Estimated ovulation
—Most fertile window
How it's calculated
Estimates ovulation as roughly 14 days before your next period (next period = last period + cycle length), with the fertile window being the five days before ovulation plus the day itself, when conception is most likely. This is an estimate for a regular cycle and is not a contraceptive method — real cycles vary, and this can't detect ovulation directly. Not medical advice; see a doctor for family-planning guidance.