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Pregnancy Due Date Calculator

Estimated due date and how far along you are, from your last period.

How to use

  1. Enter the first day of your last menstrual period.
  2. Adjust the average cycle length if it isn't 28 days.
  3. See the estimated due date, current week and trimester.

Frequently asked questions

How is the due date calculated?

Naegele's rule: LMP + 280 days, shifted by how your cycle differs from 28 days. Ultrasound dating from your provider is more precise.

How likely is birth on the due date?

Only ~4% of babies arrive exactly on it - most come within two weeks either side.

Is this medical advice?

No - an estimate for information. Your prenatal care provider's dating and guidance take precedence.

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