Ovulation Calculator (Fertile Days)
Ovulation calculator: estimated ovulation day and fertile window for the next three cycles from your last period and cycle length.
Ovulation ≈ next period − 14 days
How to use this calculator
- Type your input in the box.
- The result updates as you type.
- Use “Copy result” or “Copy link” to share it.
Ovulation usually happens about 14 days before the next period. The fertile window spans the 5 days before ovulation and the day after.
Cycles vary; ovulation tests or temperature tracking are more precise.
For general information only; it does not replace advice from a doctor or other health professional.
Frequently asked questions
Period started November 1 with a 28-day cycle?
Ovulation around November 15; fertile November 10–16.
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