Due Date Calculator
Calculate your pregnancy due date and track important milestones throughout your pregnancy
Most women have 28-day cycles
Enter Your Information
Fill in the form and click "Calculate Due Date" to see your pregnancy timeline
How Due Dates Are Calculated
The most common method for calculating your due date is Naegele's Rule, which adds 280 days (40 weeks) to the first day of your last menstrual period. This assumes a 28-day menstrual cycle with ovulation occurring on day 14. If your cycle is longer or shorter, the calculator adjusts for this.
The Three Trimesters
Pregnancy is divided into three trimesters, each lasting about three months. The first trimester (weeks 1-13) is a time of rapid development. The second trimester (weeks 14-27) is often called the "golden period" when many women feel their best. The third trimester (weeks 28-40) is when the baby gains most of their weight and prepares for birth.
When Will You Actually Deliver?
Despite what the name suggests, your "due date" is really more of a "due month." Studies show that only about 5% of babies are born on their exact due date. Most babies arrive within two weeks before or after the estimated due date. First-time mothers are slightly more likely to deliver after their due date, while women who have given birth before may deliver a bit earlier.
Your healthcare provider will use early ultrasounds to refine your due date, as measurements taken in the first trimester are the most accurate way to date a pregnancy. They'll continue to monitor your baby's growth throughout pregnancy to ensure everything is progressing normally.