🤰 Pregnancy Due Date Calculator
Estimate your due date, track pregnancy weeks, and discover weekly baby development milestones.
Average Pregnancy
40 Weeks
Heartbeat Detected
Week 6
First Movement
Week 18-22
Lungs Mature
Week 36
Calculate Your Due Date
Ultrasound Dating (Optional)
If you've had an early ultrasound, enter the gestational age for more accuracy.
Ultrasound date: --
Naegele's Rule
The standard method adds 280 days (40 weeks) to the first day of your last period. For conception date, add 266 days (38 weeks).
Ultrasound Accuracy
First trimester ultrasound (8-12 weeks) is most accurate for dating. Later ultrasounds are less precise for determining due date.
Only 5% Are On Time
Only 5% of babies arrive exactly on their due date. Most are born between 38-42 weeks. The due date is an estimate, not a deadline.
Frequently Asked Questions
What if I don't know my LMP or conception date?
An early ultrasound between 8-12 weeks is the most accurate way to date a pregnancy. The ultrasound measures the baby's crown-rump length (CRL) to estimate gestational age. If you're unsure, consult your healthcare provider.
How is my due date adjusted for twins?
Multiple pregnancies often deliver earlier. Twins average 35-37 weeks, triplets 32-35 weeks. Your healthcare provider will monitor closely and adjust expectations based on growth and other factors.
Can my due date change?
Yes, especially if you have an early ultrasound that shows a significant discrepancy (more than 5-7 days) from your LMP-based due date. Later in pregnancy, due dates are rarely changed as measurements become less accurate for dating.
What does "full term" mean?
Full term is now classified as 39-40 weeks. Early term is 37-38 weeks, late term is 41 weeks, and post-term is 42+ weeks. Babies born at 39-40 weeks have the best health outcomes.