Pregnancy Week Calculator

Pregnancy week is calculated by dividing the number of days since the first day of the last menstrual period by 7. Medically, pregnancy duration is considered to be 40 weeks (280 days).

If you don't remember your last period date, your doctor can determine the gestational age more accurately by measuring the baby's size via ultrasound. First trimester ultrasound provides the most accurate results.

1st Trimester (0-12 weeks): Organs form, nausea is common. 2nd Trimester (13-27 weeks): Energy increases, baby movements begin. 3rd Trimester (28-40 weeks): Baby gains weight rapidly, birth preparations are made.