Estimate your baby's due date from your last menstrual period.
The standard method (Naegele's rule) adds 280 days (40 weeks) to the first day of your last menstrual period. This assumes a 28-day cycle.
Only about 5% of babies are born on their exact due date. The normal range is 38 to 42 weeks. Your doctor may adjust the estimate with an ultrasound.
This calculator is for general informational purposes only. It is not a substitute for professional medical advice.