Ovulation Estimator
A gentle sketch of your most fertile days, this cycle and the next three. Planning help, not a medical tool.
A planning estimate of when you’re most likely to ovulate, based on your last period and average cycle length.
The first day of bleeding, not the last.
From the first day of one period to the first day of the next.
How this works
Ovulation usually happens about 14 days before your next period (the luteal phase), so we estimate it at your cycle length minus 14 days after your last period started. The fertile window covers the five days before ovulation plus ovulation day, because sperm can live up to about five days.
Real cycles wobble, stress, travel, and life all shift timing. Think of these dates as a helpful sketch, not a schedule.
Sources & method
Ovulation is estimated at (cycle length − 14) days after your period starts about 14 days before the next period, the typical luteal phase. The fertile window spans the 5 days before ovulation through ovulation day. Based on ACOG and NICHD patient literature. Planning estimates only.
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