Pregnancy Due Date Calculator

Estimate your due date and see pregnancy milestones week by week.

Calculate By

First Day of Last Period

Average Cycle Length (days)

About Due Date Calculation

The estimated due date is calculated using Naegele's rule: add 280 days (40 weeks) to the first day of the last menstrual period. Only about 5% of babies are born on their exact due date. Most births occur between weeks 37-42. This calculator adjusts for cycle lengths different from the standard 28 days. Always consult with your healthcare provider for the most accurate dating.