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Ovulation calculator

Planning a baby? Calculate your most fertile days in the month.

Most fertile days
March 27, 2026 - March 31, 2026
Estimated ovulation
March 30, 2026

How to use the ovulation calculator

For a better estimate, enter the correct cycle start and average length.

Cycle start
Enter the first day of your last period.
Cycle length
Average cycle is 28 days, but it varies by woman.
Guidance
The result is an estimate; fertile days may vary.

Frequently asked questions

Is the calculation accurate for irregular cycles?

With irregular cycles accuracy is lower. Track multiple cycles for better estimates.

When is fertility highest?

Fertility is highest around ovulation and a few days before.

Can I use this as contraception?

No, the calculator is for guidance only.

When are my fertile days?

The highest chance of pregnancy is around ovulation, which happens roughly mid‑cycle. The fertile window lasts about 5 days (3 days before and 1 day after ovulation). Accuracy depends on cycle regularity.