What estimated fetal weight (EFW) means
Estimated fetal weight (EFW) is calculated from ultrasound measurements. It is not a directly measured weight, so the formula and examination context remain important.
Use the calculatorWhat EFW means
EFW means estimated fetal weight. It is calculated from ultrasound measurements and can vary by formula, equipment, fetal position, and timing.
Which weight value should I enter?
Use the estimated fetal weight, often written as EFW, from the ultrasound report. Do not enter maternal weight or a predicted birth weight from another app.
How to use the calculator
Enter the pregnancy week, days, and the estimated fetal weight from the ultrasound report. Before 22 weeks, the form switches from estimated fetal weight to fetal biometry measurements.
What should I do if the result worries me?
Ask your clinician to interpret the value together with the full ultrasound report, exam history, and local clinical guidance.