Ovulation Calculator
Estimate your ovulation date and 6-day fertile window from the first day of your last period and your average cycle length — a calendar estimate for pregnancy planning, not a contraceptive method.
Built on the Luteal Phase, Not Day 14
Ovulation happens about one luteal phase (14 days by default, adjustable) before the next period — which only equals "day 14" in a textbook 28-day cycle. Longer cycles shift ovulation later, and the calculator accounts for that.
Plan Ahead
Every result includes the expected next period, the earliest sensible pregnancy-test date, and a three-cycle forward projection of fertile windows.