How Many Weeks Pregnant Am I?
Enter your last period, conception date, or due date to find out exactly how far along you are, your trimester, due date, and key milestones.
How pregnancy weeks are counted
Pregnancy is counted from the first day of your last menstrual period (LMP) — not from the day of conception or when you got a positive test. This is a medical convention that allows consistent dating even when the exact day of conception isn't known.
Under this system, you're already considered 2 weeks pregnant at the time of conception, and about 4 weeks when you miss your first period. A full-term pregnancy runs to 40 weeks from LMP.
The three trimesters
How the due date is calculated
The standard method is Naegele's rule: add 280 days (40 weeks) to the first day of your LMP. This assumes a 28-day menstrual cycle with ovulation on day 14.
Only about 5% of babies are born exactly on their due date — it's more of a target than a deadline. Most births occur within two weeks either side. An early ultrasound will give a more accurate estimate.
Australian antenatal care schedule
A typical antenatal care schedule in Australia involves the following key appointments:
| Weeks | Appointment / test |
|---|---|
| 6–8 weeks | Confirm pregnancy, first GP visit, referrals |
| 10–13 weeks | Nuchal translucency ultrasound, first trimester screening |
| 16–20 weeks | Morphology / anatomy ultrasound |
| 24–28 weeks | Glucose tolerance test (gestational diabetes screening) |
| 28 weeks | Anti-D injection (if Rh negative), blood tests |
| 32–36 weeks | Fortnightly appointments begin |
| 36+ weeks | Weekly appointments, Group B Strep test |