Pregnancy Calculator
Find out how many weeks pregnant you are, which trimester you're in, and your estimated due date.
Pregnancy Week by Week Guide
Pregnancy is typically measured in weeks from the first day of your last menstrual period (LMP). A full-term pregnancy lasts approximately 40 weeks or 280 days. Knowing your exact week helps you understand your baby's development and what to expect.
The Three Trimesters
First Trimester (Weeks 1–13): The embryo develops rapidly. Morning sickness, fatigue, and breast tenderness are common. The heartbeat can be detected around week 6–8.
Second Trimester (Weeks 14–27): Often called the "golden period." Morning sickness subsides, energy returns. Baby movements (quickening) are felt around week 18–22.
Third Trimester (Weeks 28–40+): Baby gains weight rapidly. Braxton Hicks contractions begin. Final organ development occurs. Birth preparation begins.
How Due Date is Calculated (Naegele's Rule)
Add 280 days (9 months + 7 days) to the first day of your last menstrual period. For irregular cycles, adjustments are made based on cycle length.
Frequently Asked Questions
How many weeks is a full-term pregnancy?
40 weeks (280 days) from LMP. Babies born at 37–42 weeks are considered full term.
What are the three trimesters?
First: weeks 1–13. Second: weeks 14–27. Third: weeks 28–40+.
How is due date calculated?
LMP + 280 days (Naegele's Rule). Add 9 months and 7 days to your LMP date.