Pregnancy Calculator
Calculate your due date, current pregnancy week and trimester.
First day of last period
Due date
December 11, 2026
Currently
10w 0d
Trimester
1
Days until due
209
LMP
March 6, 2026
Conception (est.)
March 20, 2026
How pregnancy is dated
Pregnancy is counted from the first day of the last menstrual period (LMP), not conception. LMP is known; conception date usually is not.
- Due date = LMP + 280 days
- Trimester 1: weeks 1–12
- Trimester 2: weeks 13–26
- Trimester 3: weeks 27–40
Formula / How it works
Due date = Last Menstrual Period (LMP) + 280 days (40 weeks) Trimester 1: weeks 1–12 Trimester 2: weeks 13–26 Trimester 3: weeks 27–40