How it works
The Naegele rule adds 280 days (40 weeks) to the first day of your last menstrual period. This is an estimate, not a medical diagnosis.
Pregnancy Due Date Calculator
Estimate your due date and current week of pregnancy.
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Frequently asked questions
How accurate is the due date?
Only about 4% of babies are born exactly on the due date. Most arrive within two weeks before or after.