Ovulation Calculator
Calculate your estimated ovulation day and fertile window using the Ogino-Knaus method.
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Quick Summary: Ovulation Calculator
In FY 2026-27, ovulation generally occurs 14 days before your next period. Your fertile window is the 6-day period including the day of ovulation, when conception probability is highest.
How to use the Ovulation Calculator
- 1
Enter Last Period
Select the first day of your last menstrual period (LMP).
- 2
Set Cycle Length
Input the average number of days between your cycles (e.g., 28 or 30 days).
- 3
Analyze Window
Identify your ovulation day and the 'Fertile Window' highlighted for planning.