Pinpoint your most fertile days by calculating your estimated ovulation date and fertile window based on your menstrual cycle.
Ovulation is the monthly process where a mature egg is released from an ovary. The egg then travels down the fallopian tube, where it can be fertilized. This period is the most fertile time in a woman's menstrual cycle. For most women, ovulation typically occurs about 14 days before the start of their next menstrual period.
Your "fertile window" includes the day of ovulation and the five days leading up to it. Sperm can survive in the female reproductive tract for up to five days, so intercourse during this window provides the highest chance of conception.
Limitations: This calculator provides an estimate. Individual cycle lengths can vary, and factors like stress or health changes can shift the timing of ovulation.
Maintained by Live Fitness Check. Last updated: August 9, 2026. How we test our calculators .
Estimates an ovulation date and fertile window from menstrual-cycle dates and cycle length.
The calculator estimates ovulation relative to the expected next period and derives an approximate fertile window around that date. The calculation uses last menstrual period date and average cycle length.
Real ovulation timing can vary from cycle to cycle, especially with irregular cycles, illness, postpartum changes or hormonal conditions. Use the number as an estimate and consider professional advice when the result may affect health, treatment, pregnancy, nutrition, exercise safety or another important decision.
