Estimating Your Baby's Arrival
Pregnancy typically lasts 280 days (40 weeks) from the first day of your last menstrual period (LMP). This calculator uses Naegele's Rule, the standard medical formula, to estimate your date.
Trimesters Explained
- First Trimester: Weeks 1-12.
- Second Trimester: Weeks 13-26.
- Third Trimester: Weeks 27-40+.
Frequently Asked Questions
Can my due date change?
Yes, early ultrasounds are more accurate than LMP. Your doctor may adjust your date based on the baby's size.