Overview

View estimated fetal size (head circumference, abdominal circumference, femur length) and weight for each gestational week. Based on WHO and Hadlock growth charts, this tool also provides weekly developmental milestones. Actual fetal measurements should be confirmed via ultrasound.

Formula

Hadlock Estimated Fetal Weight (EFW):
log10(EFW) = 1.326 - 0.00326 x AC x FL + 0.0107 x HC + 0.0438 x AC + 0.158 x FL

(HC: Head Circumference, AC: Abdominal Circumference, FL: Femur Length, in cm)

* Enter your actual ultrasound measurements for an EFW based on the Hadlock formula.

How to Use

1. 1Enter your current gestational week.
2. 2Enter ultrasound measurements (head circumference, abdominal circumference, femur length) if available.
3. 3Click the 'Calculate' button.
4. 4The average size for that week, percentile range, and estimated weight will be displayed.

Tips

• ✔Fetal growth is assessed in percentiles; the 10th–90th percentile range is considered normal.
• ✔Estimated fetal weight (EFW) can differ from actual birth weight by approximately ±15%.
• ✔Below the 3rd percentile may indicate fetal growth restriction (FGR); above the 97th may indicate macrosomia (LGA).
• ✔Measurements can vary between sonographers, so tracking the growth trend is more important than any single reading.
• ✔This calculator is for reference; fetal growth assessment must be performed by a medical professional.

FAQ