Pregnancy & Due Date Calculator
Calculate your due date and track your pregnancy progress by trimester.
What is a Pregnancy Due Date Calculator?
A pregnancy due date calculator estimates your expected delivery date (EDD) based on the first day of your last menstrual period (LMP) or your conception date. Pregnancy typically lasts 40 weeks (280 days) from the first day of the last menstrual period, or approximately 38 weeks from conception. This calculator also determines your current trimester, weeks pregnant, and days remaining until your due date. While the calculated date is an estimate, only about 5% of babies are born on their exact due date — most arrive within two weeks before or after.
How to Calculate Your Due Date
The most common method uses Naegele's Rule: add 280 days (40 weeks) to the first day of your last menstrual period. For example, if your LMP was January 1, your estimated due date is October 8. Alternatively, add 9 months and 7 days to your LMP date. If you know your conception date, add 266 days (38 weeks). This calculator accepts both methods and instantly computes your due date, current week of pregnancy, trimester, and key milestone dates throughout your pregnancy journey.
Understanding Pregnancy Trimesters
Pregnancy is divided into three trimesters: First Trimester (weeks 1-12) — major organ development occurs, morning sickness is common, miscarriage risk is highest; Second Trimester (weeks 13-26) — often called the "honeymoon phase," energy returns, baby movements begin, anatomy scan typically performed around week 20; Third Trimester (weeks 27-40) — rapid fetal growth, preparation for birth, Braxton Hicks contractions may occur. Each trimester brings distinct developmental milestones and physical changes for both mother and baby.
Important Pregnancy Milestones
Key pregnancy milestones include: Week 6-8 — first prenatal appointment and heartbeat detection; Week 10-13 — first trimester screening (nuchal translucency scan, blood tests); Week 16-20 — anatomy ultrasound, gender determination possible; Week 24 — viability milestone (baby can potentially survive outside womb with intensive care); Week 28 — third trimester begins, glucose screening; Week 36-37 — baby considered early term; Week 39-40 — full term. Regular prenatal care appointments track these milestones and monitor maternal and fetal health throughout pregnancy.
Disclaimer and Medical Advice
This calculator provides estimated dates for informational purposes only and is not a substitute for professional medical advice. Due dates are estimates — only about 5% of babies arrive on their calculated due date. Your healthcare provider may adjust your due date based on ultrasound measurements, which are more accurate than LMP-based calculations, especially if your cycles are irregular. Always consult your obstetrician or midwife for personalized pregnancy care, medical decisions, and accurate dating based on your specific circumstances.