🤰 Pregnancy Due Date Calculator
Calculate your estimated due date and track every week of your pregnancy. Enter your last period date, conception date, or ultrasound result to get your due date, current trimester, and key milestones.
📖 How Is Your Due Date Calculated?
A typical pregnancy lasts 280 days (40 weeks) from the first day of your last menstrual period (LMP), or 266 days (38 weeks) from conception. The most common method is Naegele's Rule:
EDD = LMP + 280 days
or: LMP + 9 months + 7 days
Trimester Breakdown
- First Trimester (Weeks 1–13): Organ development, morning sickness common, highest miscarriage risk
- Second Trimester (Weeks 14–27): Energy returns, baby movements felt (~18–22 weeks), anatomy scan
- Third Trimester (Weeks 28–40): Rapid growth, birth preparation, GBS test, weekly visits
⚕️ Medical Disclaimer
This calculator provides estimates only. Only 5% of babies are born on their exact due date — most arrive within a 2-week window. Always confirm your due date with your OB/GYN or midwife via ultrasound, which is more accurate than LMP calculation.
❓ Frequently Asked Questions
How accurate is the LMP due date calculation? −
The LMP (last menstrual period) method is accurate within ±2 weeks for women with regular 28-day cycles. It can be less accurate for women with irregular cycles. First-trimester ultrasound (before 13 weeks) is the most accurate dating method, typically accurate to within ±5–7 days. When LMP and ultrasound dates differ by more than 7–10 days, doctors usually go with the ultrasound date.
What is a full-term pregnancy? +
A full-term pregnancy is defined as 39 weeks 0 days through 40 weeks 6 days. Babies born at 37–38 weeks are 'early term,' while those born at exactly 37 weeks or earlier are premature. Late term is 41 through 41w6d, and post-term is 42 weeks and beyond. Most doctors recommend inducing labor at 41–42 weeks if labor hasn't begun naturally.
Can my due date change? +
Yes. Your due date may be adjusted after an ultrasound if the baby's measurements don't match the LMP-based estimate. This is especially common if you conceived later in your cycle or have irregular periods. Only about 4–5% of babies are actually born on their calculated due date — most arrive within a 2-week window on either side.
What week is safe to deliver? +
Babies born at 39–40 weeks (full term) have the best outcomes. Earlier deliveries carry increased risks: 37–38 weeks (early term) has slightly higher NICU risk; before 37 weeks is premature. However, sometimes early delivery is medically necessary due to preeclampsia, placental issues, or other complications. Your care team will guide you on the safest timing.
What are the signs of labor? +
Early signs include: regular contractions that intensify and get closer together (unlike Braxton Hicks which are irregular), water breaking (rupture of membranes), bloody show (mucus plug discharge), and lower back pain that radiates to the abdomen. If your water breaks, contractions are 5 minutes apart lasting 60 seconds, or you have heavy bleeding, go to the hospital immediately.