🤰 Health & Body

Pregnancy Calculator

Calculate your current pregnancy week, trimester and estimated due date from your last menstrual period.

How is the due date calculated?

The most common method is Naegele's Rule, which adds 280 days (40 weeks) to the first day of your last menstrual period. Our calculator adjusts for cycles that differ from the standard 28-day cycle.

Pregnancy trimesters

First Trimester (Weeks 1–12): Rapid embryo development. Morning sickness and fatigue are common.
Second Trimester (Weeks 13–26): Often the most comfortable stage. Your 20-week morphology scan occurs here.
Third Trimester (Weeks 27–40+): Baby gains most of its weight. Birth preparation begins.

Important: This is an estimate only. Your healthcare provider will confirm your due date, usually via an ultrasound scan in the first trimester. Always follow your midwife's or obstetrician's advice.

Booking your antenatal care

In Queensland, book your first antenatal appointment as soon as you know you are pregnant — ideally before 10 weeks gestation. You can access care through a public hospital, private obstetrician or midwifery group practice.