Your estimated due date, current week, and key milestones.
The Due Date Calculator estimates your pregnancy due date and key milestones based on your last menstrual period (LMP) or conception date. Pregnancy typically lasts 40 weeks from the first day of your last period.
Pick your method: Last Menstrual Period (LMP — the most common, used by clinicians) or Conception Date if you know it. Enter the relevant date. The calculator returns your estimated due date (40 weeks from LMP, or 38 weeks from conception), your current week and day of pregnancy, your trimester, and a timeline of major milestones — first prenatal visit (~8 weeks), end of first trimester (12 weeks), anatomy scan (~20 weeks), viability (24 weeks), full term (37 weeks). Adjust the cycle-length field if your cycle is regularly longer or shorter than 28 days for a more personalised estimate.
Conception happens around day 14 of a typical 28-day cycle, but most people don't know exactly when they ovulated. They do know when their last period started. So obstetricians anchor pregnancy dating to the first day of the LMP and call that "week zero" — even though you weren't actually pregnant for the first two weeks. This is Naegele's rule, dating from the 1830s, and it's still the global standard. The result: the "40-week pregnancy" includes about 38 weeks of actual gestation. An early ultrasound (8–12 weeks) can confirm or correct the date based on embryo size.
First prenatal visit around week 8. Dating scan typically 10–13 weeks. End of first trimester at 13 weeks (miscarriage risk drops sharply). Anatomy scan around 20 weeks (a major checkpoint). Movement usually felt by 22 weeks. Glucose test 24–28 weeks. Group B strep test around 36 weeks. Full term at 37 weeks. Average labour and delivery at 40 weeks ± 2.