📆Due Date Calculator

Estimate your baby's due date from the first day of your last menstrual period (Naegele's rule).

First day of your last menstrual period

Average cycle length (days)

Based on Naegele's rule (LMP + 280 days), adjusted for your cycle length.

Estimated Due Date

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Currently

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Days to go

About the Due Date Calculator

Your estimated due date is calculated by adding 280 days (40 weeks) to the first day of your last menstrual period, adjusted for your average cycle length. Only about 1 in 20 babies arrive exactly on their due date — it is an estimate, not a guarantee. Always confirm with your healthcare provider.