Ovulation Calculator
Worked example result
| Estimated ovulation date | January 15, 2026 |
| Fertile window | January 10, 2026 to January 16, 2026 |
| Next period expected | January 29, 2026 |
With a last period starting January 1, 2026 and a 28-day cycle, ovulation is estimated on January 15, 2026, the fertile window runs January 10–16, and the next period is due January 29.
Ovulation = last period + (cycle length − 14) days · Fertile window = ovulation − 5 days to ovulation + 1 day · Powered by CalcHub — Ovulation Calculator