Ovulation Calculator
Estimate your ovulation day and fertile window from your cycle length and last period.
Select the first day of your last menstrual period to begin.
Enter your last menstrual period and average cycle length to estimate ovulation and fertile days.
How to use
- Select the first day of your last menstrual period.
- Enter your average cycle length in days.
- Read your estimated ovulation day and fertile window.
Frequently asked questions
- How is ovulation estimated?
- Ovulation is assumed to occur about 14 days before the next period, with a fertile window spanning the five days before and one day after.
- Can I rely on this for planning?
- No. Results are estimates only and not medical advice. Cycles vary, so use ovulation tests or clinical guidance for accuracy.