Pregnancy lasts approximately 280 days (40 weeks) from the first day of the last menstrual period. To calculate your due date: add 280 days to the first day of your last period. Alternatively, add 9 months and 7 days. Week 40 is the estimated due date, but normal delivery occurs between 37 and 42 weeks.
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🤰 Pregnancy Due Date Calculator
Calculate your pregnancy due date from your last menstrual period or conception date. Shows weeks pregnant, trimester, and important milestones. Free and accurate.
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✅ Trusted Tool
For educational purposes only. Always confirm due date with your healthcare provider via ultrasound. No sign-up needed.
🤔 How Does This Work?
LMP method: add 280 days (adjusting for cycle length variation)
Conception method: add 266 days
Shows current week, trimester, and key milestones
❓ Frequently Asked Questions
How accurate is the due date calculation?▼
Only about 5% of babies are born on their exact due date. Most births occur between 37-42 weeks (term pregnancy). The due date is a 40-week estimate from LMP, which assumes a 28-day cycle and ovulation on day 14. Ultrasound dating in the first trimester is generally more accurate. Your due date is an estimate, not a deadline.
What are the three trimesters?▼
First trimester: weeks 1-12. Major organ development occurs. Morning sickness common. Highest miscarriage risk. Second trimester: weeks 13-27. Baby movements felt. Most women feel better. Major growth period. Third trimester: weeks 28-40+. Rapid weight gain. Preparation for birth. Baby positions for delivery.
Only about 5% of babies are born on their exact due date. Most births occur between 37-42 weeks (term pregnancy). The due date is a 40-week estimate from LMP, which assumes a 28-day cycle and ovulation on day 14. Ultrasound dating in the first trimester is generally more accurate. Your due date is an estimate, not a deadline.
What are the three trimesters?▼
First trimester: weeks 1-12. Major organ development occurs. Morning sickness common. Highest miscarriage risk. Second trimester: weeks 13-27. Baby movements felt. Most women feel better. Major growth period. Third trimester: weeks 28-40+. Rapid weight gain. Preparation for birth. Baby positions for delivery.