EDD Calculator

Estimated due date using Naegele's rule — by last menstrual period or conception date. Shows gestational age, trimester, and key milestones.

Calculate due date

First day of last menstrual period (LMP)

Average cycle length (days) Default 28 days. Adjust if your cycle is longer or shorter.

Naegele's Rule: EDD = LMP + 280 days (40 weeks). Adjusted for cycle length variation. Ultrasound dating takes precedence when available.

Results

Enter dates above to calculate your due date

Source: ACOG Committee Opinion — Methods for Estimating Due Date. Reviewed Sep 2026.

Important: EDD is an estimate. Ultrasound dating — especially in the first trimester — is more accurate and takes clinical precedence. Only about 5% of babies are born on their exact due date. Always confirm dates with your obstetric team.