Pregnancy Due Date Calculator

Use our accurate Pregnancy Due Date Calculator to estimate your baby's arrival. Calculations are based on the standard 40-week gestation period, as referenced by the American College of Obstetricians and Gynecologists (ACOG).

First Day of Last Period (LMP)

Calculation Method (Naegele's Rule)

The estimated due date is calculated by adding 280 days (40 weeks) to the first day of your last menstrual period:

$$Due Date = LMP + 280 days$$

Reference: American College of Obstetricians and Gynecologists (ACOG). Standards for pregnancy dating.

Frequently Asked Questions

Is the due date always accurate?

Only about 5% of babies are born exactly on their due date. It is an estimate, and most babies arrive within two weeks before or after.

What if my cycle is not 28 days?

LMP-based calculation assumes a standard 28-day cycle. If your cycle varies, your doctor may use an ultrasound for a more precise date.