Due Date Calculator
Calculate your estimated due date based on your last menstrual period using Naegele's Rule
Common Questions
How accurate is the due date calculation?
The due date is estimated using Naegele's Rule, adding 280 days to your LMP. Only about 5% of babies arrive on their exact due date—most come within 2 weeks before or after.
What if my cycle isn't 28 days?
We adjust the calculation based on your cycle length. Longer cycles mean ovulation occurs later, shifting your due date forward. Shorter cycles shift it earlier.
When should I see my doctor?
Schedule your first prenatal visit as soon as you have a positive pregnancy test, typically between 6-8 weeks. Your provider may adjust your due date based on early ultrasound measurements.