Health
Due Date Calculator
Calculate your estimated pregnancy due date from your last menstrual period or conception date, with gestational age and trimester.
days
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Estimated Due Date
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Weeks Along
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Days Remaining
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Estimated Conception
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LMP Estimate
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How Due Dates Are Calculated
Using Naegele's rule: add 280 days (40 weeks) to the first day of your last menstrual period. This is adjusted for cycle lengths other than 28 days — longer cycles push the due date later, shorter cycles push it earlier.
From conception date, due date is 266 days (38 weeks) later. Gestational age is measured from LMP, so conception-based inputs are converted back to equivalent LMP. Due dates are estimates — only about 5% of babies are born on their exact due date.