Due Date Calculator
Calculate your estimated date of confinement (EDD) using Naegele's Rule and Mittendorf-Williams models.
Input Parameters
Enter details for calculation.
Days to Birth
Expert Tip
Only about 4% of babies are born on their exact due date. Most are born within 10 days before or after.
Calculation Methodology & Details
Formula
Calculates the standard 40-week (280-day) gestational period adjusted for cycle length.
Important Disclaimer
The calculations provided are for educational and general informational purposes only. They do not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider.
How Due Date is Calculated
Follow these steps to use this calculator:
Enter Period start
Enter days elapsed since your last period started.
Set Cycle Length
Default is 28 days.
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ℹ️ About this Calculation
This obstetrics and gynecology calculator provides accurate gestational dating, fetal biometry estimations, risk stratification, and maternal health tracking based on ACOG guidelines and clinical ultrasonography standards.
Variable Glossary
Clinical Parameters
Last menstrual period (LMP), ultrasound biometric measurements (CRL, BPD, AC, FL), or lab hCG levels.
Obstetric Metrics
Estimated due date (EDD), gestational age in weeks/days, fetal growth percentiles, and risk scores.
How to Calculate Step-by-Step
Step 1
Enter your last menstrual period (LMP) date or ultrasound biometry values.
Step 2
Select cycle length parameters or maternal clinical characteristics if required.
Step 3
Review calculated due date timeline, milestone projections, or risk scores immediately.