Enter your last period date and cycle length to estimate your ovulation day and fertile window for the next three cycles, along with your expected next period. It is useful when planning a pregnancy.
How to use it
- Pick the first day of your last period.
- Enter your cycle length.
- Read your fertile window, ovulation day and next period for three cycles.
Questions about this tool
How is ovulation estimated?
Ovulation usually happens about 14 days before the next period. The fertile window is about five days before ovulation, the day itself and the day after.
Can I use this as birth control?
No. Ovulation can shift from month to month, so this tool is not a reliable way to prevent pregnancy.