child_friendly Pregnancy Due Date Calculator

Find your estimated due date.

Enter the first day of your last menstrual period to get your due date and trimester dates.

How this calculator works

This calculator uses Naegele's rule, the standard method doctors use to estimate a due date: add 280 days (40 weeks) to the first day of your last menstrual period. If your average cycle is longer or shorter than 28 days, the estimate is adjusted accordingly.