Mean Sac Diameter Calculator

Calculate mean gestational sac diameter. Early pregnancy dating.

Sac Measurement

Measurement Unit

Msd

Dating Result

Gestational Age6w 3dEstimated

MilestoneYolk sac should be seen

Total Pregnancy Days45days

Ultrasound Benchmarks

2–3 mmSac first detected (~4.5w)

8 mmYolk sac expected

25 mmViable embryo expected

Disclaimer: This tool is for informational purposes only and is not a substitute for professional medical advice.

About this calculator

Overview

MSD for early dating. GA ≈ MSD + 30 days.

Fun Facts

Formula: MSD = (L + W + H) / 3. GA days ≈ MSD + 30.