Health & Fitness
Fetal Weight Percentile Calculator
Estimate fetal weight percentile by gestational age.
Formulas and edge cases are reviewed against authoritative references before publication. For methodology, editorial standards, or corrections, use the links below.
Frequently asked questions
What percentile is normal?
10th to 90th percentile is typically considered normal. Below 10th may indicate growth restriction.
How accurate are ultrasound weights?
Estimates can be off by 10-15%, especially in late pregnancy.
What if baby is small/large?
Your doctor will monitor closely. Many factors affect size, and one measurement isn't definitive.
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About this tool
This Fetal Weight Percentile Calculator turns your inputs into practical results. Provide Gestational Age (weeks) and Estimated Fetal Weight to calculate Small for Gestational Age and Appropriate for Gestational Age.
Adjust values to compare scenarios and see how sensitive the result is. The calculation uses the numbers as entered, so double-check units and expect small differences from rounding in the displayed totals.