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Fetal Weight Estimation (Hadlock Formula) Calculator

EFW from BPD, AC, FL — Hadlock ultrasound formula.

Estimates fetal weight (EFW) using the Hadlock 3-parameter formula from biparietal diameter (BPD), abdominal circumference (AC), and femur length (FL).

Nadia Almasri By Nadia Almasri
Published Last reviewed 1 min read

Inputs

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

log10(EFW) = 1.3596 + 0.0064×AC + 0.1424×BPD + 0.1623×FL − 0.000876×BPD×AC

In depth

Estimates fetal weight (EFW) using the Hadlock 3-parameter formula from biparietal diameter (BPD), abdominal circumference (AC), and femur length (FL).