How to interpret this estimate

Estimate ovulation timing for a regular menstrual cycle. Estimates ovulation at approximately 14 days before the next expected period.

When this result is useful

Use this calculator to compare how Period start year, Period start month, Period start day, and Average cycle length change Estimated ovulation date and Estimated cycle day, and to review alternative values before using the estimate for planning.

Common limitations

Irregular cycles, illness, stress, age, breastfeeding, and hormonal conditions can change ovulation timing. This calculator is not a contraceptive method or a fertility diagnosis. Review the units and assumptions before interpreting the result.

This calculator uses the selected inputs and the fixed formula behind the tool to produce an estimate. Review the units, assumptions, and result labels before using the output for planning.

Health results are screening or planning estimates only. They do not diagnose health status or replace advice from doctors, dietitians, or qualified healthcare professionals.

Read the medical disclaimer for more context.