Congratulations! Find out when your baby is due and track your pregnancy week by week.
Choose your calculation method below
Enter your information on the left to see your estimated due date and pregnancy timeline.
Make sure you're taking the right prenatal vitamins for your baby's development.
Find the Best Prenatal Vitamins →Due dates are calculated using Naegele's rule, which has been used since the 1800s. It assumes a 28-day menstrual cycle and calculates your due date as 280 days (40 weeks) from the first day of your last menstrual period (LMP).
If you know your conception date, we add 266 days (38 weeks) since conception occurs about 2 weeks after the start of your last period.
Only about 5% of babies are born on their exact due date. Most babies arrive within two weeks before or after. Your due date is an estimate — a "due month" is more accurate!
Factors that can affect accuracy include:
Your healthcare provider will likely confirm or adjust your due date at your first ultrasound, typically between 8-12 weeks. Early ultrasounds are the most accurate way to date a pregnancy, especially if your cycles are irregular.
Beyond your due date, here are other important pregnancy milestones: