Pregnancy Due Date

Calculate your estimated due date (EDD) using Naegele's rule. Track your progress through each trimester.

Estimated Due Date

Select LMP date

40 weeks from your last period

Important Note

This is an estimate based on Naegele's rule. Only about 5% of babies are born on their exact due date. Your healthcare provider may adjust this date based on ultrasound measurements.

Documentation

Naegele's Rule

Naegele's Rule was developed in the 1800s and remains the standard for estimating due dates. It assumes a 28-day cycle with ovulation on day 14.

The Formula

"LMP + 280 days = Estimated Due Date (or LMP + 1 year − 3 months + 7 days)"

Trimester Breakdown

1st Trimester: Weeks 1-12

2nd Trimester: Weeks 13-26

3rd Trimester: Weeks 27-40

Full term is considered 37+ weeks