Fetal Weight Calculator

Estimate fetal weight (EFW) from ultrasound biometry measurements using Hadlock and Shepard formulas.

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Important Health Disclaimer

This calculator provides general health information based on standard medical formulas and WHO guidelines. Results are for informational and educational purposes only and should not be considered as professional medical advice, diagnosis, or treatment recommendations.

For health concerns, medical conditions, fitness plans, or dietary decisions, please consult with qualified healthcare professionals, licensed physicians, registered dietitians, or certified fitness trainers who can evaluate your individual health status and medical history.

Individual health needs vary significantly. These calculations are general estimates and may not be appropriate for everyone, especially those with existing medical conditions, pregnant women, children, or elderly individuals.

Not a substitute for professional medical advice

Gestational Age

Ultrasound Measurements

mm

Head width measurement

mm

Head circumference

mm

Belly circumference

mm

Thigh bone length

Estimated Fetal Weight

0 g

0 lbs 0.0 oz

👶EFW (Primary)
0 g
📅Gestational Age
32.0 weeks
📊Expected 50th %ile
118665 g
📈Average (Hadlock)
0 g

Growth Assessment

Small for gestational age (SGA)

Deviation from expected: -100%

Formula Comparison

Hadlock (BPD,HC,AC,FL): 0 g

Hadlock (BPD,AC,FL): 0 g

Hadlock (HC,AC,FL): 0 g

Hadlock (AC,FL): 0 g

Shepard (BPD,AC): 0 g

Accuracy Note

±15% is typical for ultrasound EFW. Actual birth weight may vary.

About Fetal Weight Estimation

Measurements

  • BPD: Biparietal diameter (head width)
  • HC: Head circumference
  • AC: Abdominal circumference
  • FL: Femur length

Clinical Notes

  • SGA: <10th percentile
  • LGA: >90th percentile
  • Hadlock is most widely validated
  • AC is most predictive of weight
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sources

  • World Health Organization (WHO) — Global health metrics, disease classification, and nutritional standards. who.int
  • Centers for Disease Control and Prevention (CDC) — Health statistics, BMI guidelines, and disease prevention data. cdc.gov
  • National Institutes of Health (NIH) — Medical research, clinical guidelines, and health calculators. nih.gov
  • Mayo Clinic — Clinical health information, disease reference, and wellness guidance. mayoclinic.org

For a complete list of all references used across the site, visit our full sources page.

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Editorial Note

MyCalcBuddy Editorial Team

This page is maintained as an educational calculator reference.

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Formula Source: WHO Health Metrics Standards

by World Health Organization

🔄Last reviewed: May 2026
✓Formula checks are based on standard references and internal QA review.