Hadlock Estimated Fetal Weight (BPD/HC/AC/FL)
Hadlock estimated fetal weight (four-parameter model) from biparietal diameter, head circumference, abdominal circumference, and femur length (all in centimeters).
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Biparietal diameter
- 9.0 cm
- Head circumference
- 33.0 cm
- Abdominal circumference
- 30.0 cm
- Femur length
- 7.0 cm
Result: Estimated fetal weight 2600 g (Hadlock four-parameter model).
The tool opens with these values already filled in. Replace them with your own.
What the result means
- Use
- a point weight estimate; the growth-percentile reading and the growth-restriction or macrosomia decision stay with the clinician.
What you enter
- Biparietal diameter
- Head circumference
- Abdominal circumference
- Femur length
How this is calculated
- Formula
- log10(EFW g) = 1.3596 - 0.00386 x AC x FL + 0.0064 x HC + 0.00061 x BPD x AC + 0.0424 x AC + 0.174 x FL; biometry in cm.
Hadlock FP, Harrist RB, Sharman RS, Deter RL, Park SK. Estimation of fetal weight with the use of head, body, and femur measurements -- a prospective study. Am J Obstet Gynecol. 1985;151(3):333-337. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.