Estimate your ovulation date and fertile window for the next six cycles from your last period, cycle length and luteal phase, with test dates.
About this tool
Estimate your ovulation day and fertile window for the next cycles.
How to use Ovulation Calculator
- Enter the first day of your last period.
- Enter your average cycle length and luteal phase.
- Read the next ovulation date, fertile window and upcoming cycles.
Worked example
With a 28-day cycle and 14-day luteal phase, ovulation falls around day 14 and the fertile window runs from about day 9 to day 15.
What is the fertile window?
The five days before ovulation and the day after, when pregnancy is most likely.
Can I use this as contraception?
No. Cycles vary; use ovulation tests or temperature tracking for more accuracy, and proper contraception to avoid pregnancy.
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