Estimated Due Date
Pregnancy Progress
Key Milestones
How is the due date calculated?
This calculator uses Naegele's rule, the standard method used by most healthcare providers. When you enter the first day of your last menstrual period, the calculator adds 280 days (40 weeks) to arrive at your estimated due date. If you enter a conception date instead, it adds 266 days (38 weeks), since conception typically happens about two weeks after the start of your last period.
How accurate is this?
Only about 5% of babies arrive on the exact due date. Most are born within two weeks before or after. Your due date is best understood as the middle of a window rather than a fixed deadline. Factors like cycle length, the timing of ovulation, and whether this is a first pregnancy can all shift the actual delivery date.
Disclaimer: This calculator provides an estimate only. It is not a substitute for professional medical advice. Consult your healthcare provider for personalized prenatal care and a more precise due date based on ultrasound measurements and your individual health history.