Ovulation & fertile window
Estimate your ovulation date, fertile window and potential due date from the first day of your last period and cycle length.
Open calculatorPregnancy & due date
Uses Naegele’s rule (first day of last menstrual period + 280 days, adjusted for how your cycle length differs from 28 days) to estimate your due date, current gestational week and conception window.
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Educational estimate only. Not medical, tax, legal or financial advice.