Pregnancy Due Date Calculator
Calculate your estimated due date
The first day of your last period
days
Typical range is 21-35 days (average is 28)
Pregnancy Milestones
- Week 4: Missed period, early pregnancy tests positive
- Week 8: First prenatal visit typically scheduled
- Week 12: End of first trimester, lower miscarriage risk
- Week 20: Anatomy scan, may learn baby's sex
- Week 28: Third trimester begins
- Week 37: Full term pregnancy
- Week 40: Due date (average pregnancy length)
How It's Calculated
Naegele's Rule:
Due Date = LMP + 280 days (40 weeks)
Adjusted for cycle length:
Due Date = LMP + 280 + (cycle length - 28) days
Due Date = LMP + 280 days (40 weeks)
Adjusted for cycle length:
Due Date = LMP + 280 + (cycle length - 28) days
This calculator provides an estimate. Only about 5% of babies are born on their due date. Most babies arrive within 2 weeks before or after.