Ovulation Calculator
Estimate ovulation day and fertile window.
Average cycle is 28 days. Range: 21-35 is common.
Estimated Ovulation Day
Fertile Window
6-day window (5 days before + ovulation day)
Next Period
Next 3 Cycles
Estimates based on the calendar method. Ovulation typically occurs 14 days before the next period.
Enter the first day of your last period and your cycle length to estimate your fertile window.