Due Date Calculator

Estimate your baby’s due date from your last period.

Due Date Calculator

Estimate your baby's due date from the first day of your last menstrual period.

First day of last period (LMP)

Estimated due date (EDD)

Conception estimate

Weeks of gestation

Enter the first day of your last period and press Calculate.

How the due date is estimated

The standard Naegele's rule estimates your due date by adding 280 days (40 weeks) to the first day of your last menstrual period.

Due date = LMP + 280 days
Conceived = LMP + 14 days

Because conception typically occurs about two weeks after the period starts, this tool assumes a standard 28-day cycle. Only a small fraction of babies arrive on their exact due date.