Pregnancy Due Date Calculator

Calculate due date, current week, and key pregnancy milestones

Calculate from

First day of last period

Average cycle length (days)

Estimated Due Date (EDD)

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Current week

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Current trimester

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Days pregnant

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Weeks remaining

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Key milestones

End of 1st trimester (Week 13)—

Anatomy scan (Week 20)—

End of 2nd trimester (Week 27)—

Full term (Week 37)—

Due date (Week 40)—

About Due Date Calculation

How is the due date calculated?

The standard method (Naegele's rule) adds 280 days (40 weeks) to the first day of the last menstrual period. This assumes a 28-day cycle. For longer or shorter cycles, the ovulation date is adjusted accordingly.

How accurate is the due date?

Only about 5% of babies are born on their exact due date. Most babies arrive within 2 weeks before or after the EDD. An ultrasound scan in the first trimester gives the most accurate due date.