Pregnancy Due Date Calculator

Estimate a due date from the first day of the last menstrual period.

About this tool

A due date is estimated at 280 days from the first day of your last period. Only about 5 percent of babies arrive on that exact day.

How to use Pregnancy Due Date Calculator

  1. Choose the first day of the last period.
  2. Read the estimated due date.
  3. Share the estimate with your doctor.

Frequently asked questions

How is it calculated?

Naegele's rule: add 280 days (40 weeks) to the first day of the last period.

Is it medical advice?

No. Your doctor confirms dates with an ultrasound.