Ovulation window
A fertile window and a due-date sketch from the last period and cycle length.
Open a calculatorPregnancy
The due date is the first day of the last period plus 280 days, shifted by how the cycle differs from 28 days (Naegele’s rule). Ovulation is estimated as cycle length minus 14 days. The fertile window is the five days before ovulation and the ovulation day itself. Fewer than 4% of births fall on the exact due date. This is not a diagnosis.
Estimated due date
2027-05-08
Gestational age today
8w 0d
Trimester
1
Estimated ovulation
2026-08-15
Fertile window
2026-08-10 – 2026-08-15
Estimated due date: 2027-05-08
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An educational estimate. Not medical, tax or credit advice.