Pregnancy Calculator

Free pregnancy calculator — updated for 2025. Accurate, instant, no sign-up needed.

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Pregnancy Due Date Calculator

Calculate due date, pregnancy week & trimester

Calculation Method

First Day of Last Period

Cycle Length (days)

Due Date

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Current Week

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Trimester

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Conception Date

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Days Remaining

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Viability (24 wks)

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How Is the Due Date Calculated?

Naegele's Rule: add 280 days (40 weeks) to the first day of your last menstrual period. Cycle length adjustment corrects for cycles shorter or longer than 28 days.

⚠️ Estimates only — actual due dates are confirmed by ultrasound. Only ~5% of babies are born on their exact due date.