Ovulation Calculator
Estimate your fertile window and ovulation date.
This is a general calendar estimate, not medical advice. Cycles vary month to month, so treat these dates as a rough guide. Talk to a healthcare professional for family planning or fertility concerns.
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Frequently asked questions
It works from your last period and average cycle length. Your next period is estimated as the last period plus your cycle length, and ovulation is placed your luteal-phase length (14 days by default) before that. With a 28-day cycle and a 14-day luteal phase, that lands on cycle day 14.
It is the span when conception is most likely: the five days before ovulation through the day after. Sperm can survive in the body for up to about five days, and the egg lives roughly 24 hours, so this range captures the days that matter most.
It is only a rough guide. Real cycles vary in length from month to month, and ovulation can shift, so the actual day may differ from the estimate. Ovulation predictor kits or tracking basal body temperature give a more personal picture.
No. This is a general-information estimate, not medical advice. For family planning, trouble conceiving, or any concerns about your cycle, talk to a qualified healthcare professional.
Last updated 2026-06-23.