Track your week, trimester and countdown to due date
The Pregnancy Calculator works out your current gestational age in weeks and days, your trimester, and your estimated due date (EDD) — all based on either your last menstrual period (LMP) or a known conception date. It also shows key milestones and which week-by-week developments to expect.
Gestational age is measured from the first day of your last menstrual period (LMP), not from conception. Enter your LMP date and the calculator adds 280 days (40 weeks) to give your estimated due date, then works backwards to show how far along you are today.
Gestational age counts from your LMP and is the standard used by doctors and midwives. Fetal age (or embryonic age) counts from conception, which is typically about 2 weeks less than gestational age.
The EDD is an estimate based on a standard 28-day cycle. Only about 5% of babies are born on their exact due date. Your midwife or doctor may adjust the EDD after an ultrasound scan for greater accuracy.
The first trimester runs from week 1 to week 12, the second trimester from week 13 to week 26, and the third trimester from week 27 to week 40 (or birth). The calculator shows your current trimester automatically.
Yes — select "Conception date" from the input mode toggle. The calculator adds 266 days (38 weeks) from conception to give your estimated due date.
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