Ovulation Calculator

How It Works

Ovulation usually happens about 14 days before your next period starts, so the calculator counts forward from the first day of your last period by your cycle length minus 14 to estimate the ovulation date. It then marks the fertile window as the five days before ovulation plus the day itself, the span when conception is most likely. These are estimates based on an average cycle, so pairing them with ovulation kits or temperature tracking gives the most reliable picture.

Ovulation Day ≈ LMP + (Cycle Length − 14)
Fertile Window = 5 days before to 1 day after ovulation

Examples

Frequently Asked Questions