Fetal Weight Calculator (Hadlock)
Estimate fetal weight from ultrasound measurements using the Hadlock formula.
Estimated Fetal Weight
Educational estimate only. Fetal growth should be assessed by your doctor using full ultrasound data.
About estimating fetal weight
Estimated fetal weight (EFW) is calculated from ultrasound measurements to track growth and detect growth issues.
The Hadlock formula is widely used. A full EFW uses BPD, HC, AC and FL; this tool uses a simplified AC + FL version.
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Fetal weight FAQ
How is fetal weight estimated?
From ultrasound measurements using the Hadlock formula.
Is the estimate accurate?
It has a margin of error (~10–15%); trend over time matters more than one number.
What if the baby is small or large?
Your doctor will assess growth pattern and advise follow-up.