Calculate your estimated due date (EDD), current week of pregnancy, trimester dates, and key development milestones. Enter your last period or conception date. Free, no signup.
Calculate Due Date
Estimated Due Date
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Pregnancy Progress
Week 1Week 40
Key pregnancy milestones:
⚠️ This calculator provides estimates based on standard 280-day pregnancy duration. Actual due dates vary — only a healthcare provider can give a medically confirmed due date. Consult your OB, midwife, or GP for prenatal care.
How Due Dates Are Calculated
The standard method (Naegele's Rule) adds 280 days (40 weeks) to the first day of the last menstrual period (LMP). This assumes a 28-day cycle with ovulation on day 14. For cycles longer or shorter than 28 days, the ovulation offset adjusts the calculation.
Trimester breakdown
First trimester: Weeks 1–13 (conception through week 13). Highest miscarriage risk, major organ development, most intense morning sickness.
Second trimester: Weeks 14–26. Often called the "honeymoon trimester" — energy returns, bump becomes visible, baby's movements felt (quickening) around week 18–22.
Third trimester: Weeks 27–40. Rapid weight gain, baby's organs mature, preparation for birth. Preterm birth occurs before 37 weeks; term is 37–42 weeks.
Frequently Asked Questions
How accurate is the estimated due date?
Only about 4% of babies are born on their exact due date. 70% of babies are born within 10 days before or after the EDD. Ultrasound dating (especially in the first trimester) is more accurate than LMP calculations, as it measures actual fetal size rather than assuming average cycle length.
What is considered full term?
Full term is 39–40 weeks gestation. Early term is 37–38 weeks, late term is 41 weeks, and post-term is 42+ weeks. Babies born at 37–38 weeks are technically "term" but have slightly higher risks of breathing difficulties and feeding challenges compared to 39–40 week babies.
When should I see a doctor after a positive pregnancy test?
Most OBs and midwives recommend scheduling your first prenatal appointment at 8–10 weeks. If you have a history of pregnancy complications, are over 35, or have chronic health conditions, call earlier. The first appointment typically includes a dating ultrasound, blood work, and your first prenatal check-up.