Analyze ultrasound biometrics using established fetal weight equations. Switch units, compare models, and inspect plotted results. Export clean summaries for teaching, audits, and research workflows.
The chart compares estimated weights generated from every equation supported by the entered measurements.
| Case | GA (weeks) | BPD (mm) | HC (mm) | AC (mm) | FL (mm) | Equation | Estimated weight |
|---|---|---|---|---|---|---|---|
| Example A | 28.0 | 72 | 262 | 240 | 52 | Hadlock 4 | 1,168 g |
| Example B | 32.0 | 82 | 295 | 284 | 61 | Hadlock 4 | 1,922 g |
| Example C | 36.0 | 90 | 325 | 320 | 70 | Hadlock 4 | 2,842 g |
Estimated fetal weight is commonly calculated from ultrasound biometry. Typical measurements include biparietal diameter, head circumference, abdominal circumference, and femur length. Many systems use Hadlock equations, while some also offer Shepard for BPD and AC.
For this calculator, measurements are converted to centimeters internally. The selected equation computes log10 of fetal weight, then the value is transformed back into grams. That makes it possible to compare several published equations using the same biometry set.
These biometric inputs are commonly used for ultrasound-based estimated fetal weight, and professional guidance notes that such estimates can differ meaningfully from actual birth weight. Equation choice and interpretation should stay tied to clinical review, especially when growth restriction is suspected. :contentReference[oaicite:0]{index=0}
It estimates fetal weight from ultrasound biometric measurements such as BPD, HC, AC, and FL. The result is an estimate, not an exact birth weight.
Hadlock 4 is widely used when all four measurements are available. Other options help when fewer inputs are recorded or when comparison between formulas is useful.
Yes. Choose millimeters in the unit field. The page converts them to centimeters internally before applying the selected fetal weight equation.
Each equation was derived from a different statistical model and measurement combination. Small differences are normal and show why clinical interpretation matters.
No. It is best used for study, audit, education, or general estimation support. Medical decisions should rely on qualified obstetric or maternal-fetal medicine review.
Choose an equation that matches the measurements you do have. For example, Shepard needs BPD and AC, while Hadlock 1 uses AC and FL.
Not directly in these equations. Gestational age helps with interpretation against growth expectations rather than the raw estimated weight computation itself.
Professional guidance notes that ultrasound weight estimates can deviate materially from actual birth weight, so results should be treated as approximate rather than exact. :contentReference[oaicite:1]{index=1}
The Hadlock and Shepard equations used here follow published forms summarized in clinical calculator references. Common ultrasound biometric inputs include BPD, HC, AC, and FL. :contentReference[oaicite:2]{index=2}
This page is suitable for educational and workflow support. It should not replace professional interpretation, formal ultrasound reporting, or individualized medical care.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.