How Many Weeks Pregnant Am I?
Enter your last period date to find out exactly how far along you are, what's happening with baby this week, and what milestones are coming up.
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Download Go Go GaiaCommon Questions About Pregnancy Weeks
Your pregnancy is counted from the first day of your last menstrual period (LMP) — not from conception. So when your period is a week late, you're technically already about 5 weeks pregnant. Enter your LMP date into the calculator above to get your exact week and day count, plus your trimester and due date.
Pregnancy is dated from the first day of your last period because that's a date most people can pinpoint — ovulation and conception dates are harder to know for sure. From your LMP, your doctor counts forward 280 days (40 weeks) to estimate your due date. The first two weeks of your "pregnancy" are actually before ovulation even happens, which feels weird but it's how the math works.
The first trimester covers weeks 1 through 12 — this is when morning sickness, exhaustion, and sore breasts tend to peak. The second trimester runs from week 13 to 26, and most people feel their best during this stretch (hello, energy boost). The third trimester is weeks 27 through 40, when baby is packing on weight and you're getting ready for delivery.
Baby's size changes fast! At 8 weeks, they're about the size of a raspberry. By 20 weeks — the halfway point — they're banana-sized. And by 40 weeks, you're looking at a small pumpkin (around 51 cm and 3.5 kg). Use the calculator above to see your baby's current size comparison, length, and weight for your exact week.
Gestational age counts from the first day of your last period — this is the number your doctor uses and what you'll see on ultrasound reports. Fetal age (also called embryonic age) counts from the actual date of conception, which is roughly 2 weeks less. So if you're 10 weeks pregnant by gestational age, your baby has really only been developing for about 8 weeks. Most pregnancy apps and calculators use gestational age.
Technically, no — once you're pregnant, you don't get a true period. But some people do experience light bleeding or spotting in early pregnancy, which can look a lot like a period. This is sometimes implantation bleeding (around 6-12 days after conception) or breakthrough bleeding. If you're pregnant and bleeding, it's worth mentioning to your provider just to rule out anything that needs attention.