Women & Girls Health
Menstrual Cycle Tracker
Estimate your next three periods and your fertile windows.
A menstrual cycle is counted from the first day of one period to the first day of the next, most often somewhere between 21 and 35 days, with 28 being a common average. Enter the first day of your last period and your usual cycle length, and this tool maps out what to expect next.
Cycles can vary month to month, especially in your teens, after childbirth, or near menopause. Tracking a few cycles gives a more accurate picture than any single one.
Educational only, not a medical diagnosis. Cycle timing is an estimate and isn't reliable contraception on its own.
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