Estimated Due Date Calculator

June 8, 2026

This Estimated Due Date Calculator helps you estimate your baby’s due date based on the first day of your last menstrual period.

Estimated Due Date Calculator

Your Birthdate:

Calculation Method:

First day of your last period:

Conception Date:

IVF Transfer Date:

IVF Transfer Type:

Due Date Formula

Estimated due date = first day of last period + 280 days

Parameters Explained

First day of last period: the starting date of your last menstrual cycle
280 days: the average length of a full-term pregnancy (40 weeks)

How It Works

The calculator adds 280 days to the first day of your last menstrual period to estimate the expected delivery date.

Ethan Caldwell

Ethan builds the interactive health calculators on Height Growth Blog. Based in Denver, Colorado, he combines a software engineering background with a focus on evidence-based health tech, turning dense clinical guidelines — from CDC growth charts to NIH/IOM dietary references — into tools parents and teens can use in under a minute. Every calculator on the site, from BMI Percentile to Body Fat and Calcium Intake, is built directly from primary sources (NIH, AAP, CDC, Mayo Clinic) and cross-checked against peer-reviewed studies before launch.