Health & Pregnancy
Pregnancy Due Date Calculator
Estimate your due date by LMP, conception date, or ultrasound. See current pregnancy week, trimester, and milestones.
2128 (typical)45
Estimated due date
Tue, February 2, 2027
280 days from today
Currently at
Trimester 1
0w 0d
LMP (last menstrual period)
Tue, April 28, 2026
Estimated conception
Tue, May 12, 2026
End of 1st trimester (week 13)
Tue, July 28, 2026
End of 2nd trimester (week 27)
Tue, November 3, 2026
Estimated due date (week 40)
Tue, February 2, 2027
⚕️ This is an educational estimate. Only ~5% of babies are born on their estimated due date — most arrive within 2 weeks before or after. Talk to your healthcare provider for personalized care.
Estimating a due date
Pregnancy is typically counted as 280 days (40 weeks) from the first day of your last menstrual period — even though conception happens about 2 weeks later. That convention (Naegele's rule) is universal in obstetrics. If you have a recent ultrasound, the gestational age it reports is usually more accurate than LMP, especially for irregular cycles.
Frequently Asked Questions
How is a due date calculated?▾
Naegele's rule: due date = first day of last menstrual period (LMP) + 280 days (40 weeks). For irregular cycles, the LMP method is adjusted by the cycle-length difference. Ultrasound dating (especially in the first trimester) is the most accurate method when available.
How accurate is a due date?▾
Only about 5% of babies are born on their exact estimated due date. About 80% are born between 38 and 42 weeks (within 2 weeks of the due date). Babies born before 37 weeks are "preterm"; after 42 weeks is "post-term."
What if my cycle is not 28 days?▾
Use the LMP method and adjust the cycle length slider. For longer cycles (e.g., 32 days), ovulation happens later, so the due date shifts later. For shorter cycles, it shifts earlier. Or skip LMP entirely and use conception date if you know it.
When should I have my first ultrasound?▾
A "dating ultrasound" is typically done between weeks 8 and 13. Earlier ultrasounds (before ~6 weeks) may not detect a heartbeat reliably. Switch to the "Ultrasound" method here if you have a measured gestational age.
When does each trimester start?▾
First trimester: weeks 1–13. Second trimester: weeks 14–27. Third trimester: weeks 28–40. Each transition is just a date — your body and baby keep developing on a continuous timeline.
Is this medical advice?▾
No — this is an educational estimator only. Always consult a licensed healthcare provider for personalized prenatal care, dating, and medical decisions.