🤰 Due Date Calculator
Calculate your estimated due date three different ways
Last Period
Conception Date
IVF Transfer
Your Estimated Due Date
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How is a Pregnancy Due Date Calculated?
A standard pregnancy lasts approximately 40 weeks (280 days) from the first day of your last menstrual period (LMP). This is why doctors typically calculate your due date by adding 280 days to the date your last period started — a method known as Naegele's Rule.
If you know your conception date, your due date is approximately 266 days (38 weeks) later. For IVF pregnancies, the calculation is based on the embryo's age at the time of transfer.
Only about 5% of babies are born on their exact due date. Most births occur within two weeks before or after the estimated date. Your OB-GYN will confirm your due date via ultrasound, which is the most accurate method.