Ovulation
Calculator

Estimate ovulation dates, fertile windows, and best conception days based on menstrual cycle length.

Input

Current Cycle

Estimated Ovulation

May 17, 2026

Fertile Window
FertileMay 12, 2026 – May 17, 2026
Most Fertile Days
PeakMay 15, 2026 – May 17, 2026
Ovulation Day
OvulationMay 17, 2026
Next Period
PeriodMay 31, 2026
Luteal Phase Starts
May 18, 2026

How It Works

Ovulation typically occurs about 14 days before the start of your next period (the luteal phase). The fertile window spans 6 days: the 5 days before ovulation plus ovulation day itself.

The most fertile days are the 2 days before ovulation and ovulation day, when conception is most likely.

This calculator provides estimates based on average cycle patterns. Individual cycles may vary. Consult a healthcare provider for personalized fertility guidance.

Multi-Cycle Timeline

CycleOvulationFertile WindowNext Period
Cycle 1May 17, 2026May 12, 2026 – May 17, 2026May 31, 2026
Cycle 2Jun 14, 2026Jun 9, 2026 – Jun 14, 2026Jun 28, 2026
Cycle 3Jul 12, 2026Jul 7, 2026 – Jul 12, 2026Jul 26, 2026

Learn more

How do cycle trackers predict ovulation, and why do cycle lengths vary?

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Frequently Asked Questions

Ovulation typically occurs 14 days before the start of the next menstrual period. For a 28-day cycle, ovulation falls around day 14; for longer or shorter cycles, the date shifts accordingly.

The fertile window spans the 5 days before ovulation and the day of ovulation itself, totaling approximately 6 days when conception is possible. Sperm can survive in the reproductive tract for up to 5 days.

Ovulation calculators provide estimates based on average cycle length and are most accurate for people with regular cycles. Irregular cycles, stress, illness, and hormonal changes can shift the actual ovulation date.

Ovulation Calculator - Fertile Window Estimator | ToolsCanvas