Cycle & Ovulation Tracker

Ovulation occurs when a mature egg is released from the ovary into the fallopian tube, where it can be fertilised for roughly 12 to 24 hours. In a textbook 28-day cycle, this happens on day 14, counted from the first day of the previous period. The phrase '14 days before your next period' is more accurate than '14 days after your last period', because the luteal phase - the time between ovulation and the next period - is more consistent across individuals than the follicular phase that precedes it.

The fertile window spans approximately six days: the five days before ovulation and the day of ovulation itself. Sperm can survive in the reproductive tract for up to five days, which is why conception can occur from intercourse several days before ovulation. The egg itself is only viable for about a day after release.

Cycle length varies naturally. Only about 12 per cent of cycles are exactly 28 days, and anything from 21 to 35 days is considered normal for adults. Stress, illness, travel, and significant weight changes can all shift the timing of ovulation, which is why predictions from this tool are estimates rather than guarantees.