Due Date Calculator

Calculate your baby's due date using the first day of your last period or the date of conception.

Calculation Method

First Day of Last Period

Your Due Date

Understanding "Full Term"

While 40 weeks is the target, a baby is considered full term anywhere from 39 weeks to 40 weeks and 6 days.

Term Definitions

Early Term: 37 weeks 0 days to 38 weeks 6 days.
Full Term: 39 weeks 0 days to 40 weeks 6 days.
Late Term: 41 weeks 0 days to 41 weeks 6 days.
Post Term: 42 weeks and beyond.

Why LMP?

Doctors use the Last Menstrual Period (LMP) because ovulation dates vary, but the start of a period is a distinct, observable event. An early ultrasound is usually the most accurate method to confirm gestational age.