Pregnancy Due Date Calculator
Calculate your estimated due date from your last menstrual period.
See your current week, trimester, and key pregnancy milestones.
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Estimated Due Date
Naegele’s Rule is the standard method for estimating a pregnancy due date from the last menstrual period (LMP).
Due Date = Last Period Date + 280 days (40 weeks)
Or equivalently: subtract 3 months, add 7 days, and add 1 year.
Pregnancy timeline:
- First trimester: Weeks 1–12
- Second trimester: Weeks 13–27
- Third trimester: Weeks 28–40
Key milestones:
- Week 6: Heartbeat detectable
- Week 12: End of first trimester
- Week 20: Anatomy scan (mid-pregnancy ultrasound)
- Week 24: Viability milestone
- Week 37: Considered “early term”
- Week 39–40: Full term
- Week 42: Post-term
Important notes:
- Only about 5% of babies are born on their exact due date
- Full term is considered 39 to 40 weeks
- This estimate assumes a regular 28-day cycle
- An early ultrasound provides the most accurate dating
- Always consult your healthcare provider for personalized guidance