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Calculates body mass index (kg/m²) from height and weight. For children and teens, BMI must be plotted on age- and sex-specific growth charts - this tool only shows the raw number.
Quick answer: BMI for Children Calculator
BMI = weight(kg) / height(m)^2, but children need age-and-sex percentile context rather than adult BMI bands. Use pediatric guidance for interpretation.
Example: A child 140 cm tall weighing 35 kg has BMI 17.9, but the health meaning depends on age and sex percentile charts.
Calculations follow the documented formula on this page; rounding and input units can change the last digit-treat outputs as educational estimates unless you reconcile with source systems.
* This is an estimate. Actual amounts may vary slightly based on input assumptions.
Tall-for-age kids and muscular teens skew BMI without being unhealthy; the number is a screening flag, not a verdict.
Calculates body mass index (kg/m²) from height and weight. For children and teens, BMI must be plotted on age- and sex-specific growth charts - this tool only shows the raw number.
Inputs on this page: Weight (kg), Height (cm), Age (years, optional context), Sex (for chart reminder only). Assumptions stay visible so you can reproduce the figure elsewhere.
Long-form walkthroughs that pair well with this calculator. When you need narrative context beyond the live fields, start here and return to the tool to plug in your own numbers.
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Read guide →People who care about bmi for children calculator use BMI for Children Calculator as a planning sandbox: Under-2: prefer length-weight velocity tables instead of BMI-only chats.
Continue in the Calculators category hub, the Utility tools collection, or the glossary. Related calculators in this session: Age Calculator, Daily Calorie Calculator, Anxiety Level Self-Assessment (GAD-7 style), Burnout Score Calculator, Life Expectancy Calculator, Percentage Calculator.
The Formula
BMI = weight_kg ÷ (height_m)²; pediatric percentiles require separate growth charts| This tool | BMI = weight_kg ÷ (height_m)²; pediatric percentiles require separate growth charts |
|---|---|
| Related intent: bmi for children calculator | See paired tools for bmi for children calculator-each page documents its own core relationship next to the live form. |
| Related intent: pediatric bmi calculator | See paired tools for pediatric bmi calculator-each page documents its own core relationship next to the live form. |
Core relationship for BMI for Children Calculator:
BMI = weight_kg ÷ (height_m)²; pediatric percentiles require separate growth charts
Worked check: A 10-year-old at 19 kg/m² might sit mid-chart or high depending on sex and puberty timing - only the plotted dot matters.
Keep the same assumptions and open a neighbor calculator when your question branches: Age Calculator, Daily Calorie Calculator, Anxiety Level Self-Assessment (GAD-7 style), Burnout Score Calculator. Each page documents its own formula beside the fields.
Learning links: Methodology · Editorial policy · Glossary
A child 140 cm tall weighing 35 kg has BMI 17.9, but the health meaning depends on age and sex percentile charts.
Re-enter the same numbers in the calculator above to confirm the page math matches the interactive result.
People who care about bmi for children calculator use BMI for Children Calculator as a planning sandbox: Under-2: prefer length-weight velocity tables instead of BMI-only chats.
Instant response
Run BMI for Children Calculator in the browser and read the breakdown beside the form.
Transparent formula
The formula and worked example on this page match what the calculator uses.
Privacy friendly
No account required; inputs stay in your session unless you choose to share them.
Cross-device ready
Layout works on mobile, tablet, and desktop for the same field labels.
Official references for context. Calculator outputs are planning estimates—confirm material decisions with the primary authority or a qualified professional. See our methodology and editorial policy.
Reviewed July 18, 2026 · Content stamp 2026-07-18
Click a question to expand the answer.
No. CDC/WHO percentile curves are not embedded. You need a growth chart or clinic software. For BMI for Children Calculator, keep the inputs you used beside the result so the number can be checked later. The documented formula is BMI = weight_kg ÷ (height_m)²; pediatric percentiles require separate growth charts, and small changes to rates, rounding, dates, tax rules, regional assumptions, or percentage bases can change the final bmi for children calculator result. Treat the output as a planning reference and confirm high-stakes decisions against official guidance or source systems.
It is often misleading for infants - use length-for-age and weight-for-length charts instead. For BMI for Children Calculator, keep the inputs you used beside the result so the number can be checked later. The documented formula is BMI = weight_kg ÷ (height_m)²; pediatric percentiles require separate growth charts, and small changes to rates, rounding, dates, tax rules, regional assumptions, or percentage bases can change the final bmi for children calculator result. Treat the output as a planning reference and confirm high-stakes decisions against official guidance or source systems.
No. Only a licensed clinician can assess growth and health. For BMI for Children Calculator, keep the inputs you used beside the result so the number can be checked later. The documented formula is BMI = weight_kg ÷ (height_m)²; pediatric percentiles require separate growth charts, and small changes to rates, rounding, dates, tax rules, regional assumptions, or percentage bases can change the final bmi for children calculator result. Treat the output as a planning reference and confirm high-stakes decisions against official guidance or source systems.
Convert first (lb ÷ 2.20462 ≈ kg; in × 2.54 = cm) or use a dedicated unit converter. For BMI for Children Calculator, keep the inputs you used beside the result so the number can be checked later. The documented formula is BMI = weight_kg ÷ (height_m)²; pediatric percentiles require separate growth charts, and small changes to rates, rounding, dates, tax rules, regional assumptions, or percentage bases can change the final bmi for children calculator result. Treat the output as a planning reference and confirm high-stakes decisions against official guidance or source systems.
Percentile charts are sex-specific; we remind you to use the matching CDC or WHO chart with your clinician. For BMI for Children Calculator, keep the inputs you used beside the result so the number can be checked later. The documented formula is BMI = weight_kg ÷ (height_m)²; pediatric percentiles require separate growth charts, and small changes to rates, rounding, dates, tax rules, regional assumptions, or percentage bases can change the final bmi for children calculator result. Treat the output as a planning reference and confirm high-stakes decisions against official guidance or source systems.
Same kg/m² formula as adults, but meaning lives on CDC/WHO percentile curves your pediatrician prints - not here. For BMI for Children Calculator, keep the inputs you used beside the result so the number can be checked later. The documented formula is BMI = weight_kg ÷ (height_m)²; pediatric percentiles require separate growth charts, and small changes to rates, rounding, dates, tax rules, regional assumptions, or percentage bases can change the final bmi for children calculator result. Treat the output as a planning reference and confirm high-stakes decisions against official guidance or source systems.
A 10-year-old at 19 kg/m² might sit mid-chart or high depending on sex and puberty timing - only the plotted dot matters. For BMI for Children Calculator, keep the inputs you used beside the result so the number can be checked later. The documented formula is BMI = weight_kg ÷ (height_m)²; pediatric percentiles require separate growth charts, and small changes to rates, rounding, dates, tax rules, regional assumptions, or percentage bases can change the final bmi for children calculator result. Treat the output as a planning reference and confirm high-stakes decisions against official guidance or source systems.
Under-2: prefer length-weight velocity tables instead of BMI-only chats. Ask for growth velocity (crossing percentiles) not a single visit snapshot. Sports med clinics track lean mass separately for adolescent athletes. For BMI for Children Calculator, keep the inputs you used beside the result so the number can be checked later. The documented formula is BMI = weight_kg ÷ (height_m)²; pediatric percentiles require separate growth charts, and small changes to rates, rounding, dates, tax rules, regional assumptions, or percentage bases can change the final bmi for children calculator result. Treat the output as a planning reference and confirm high-stakes decisions against official guidance or source systems.
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Reviewed by Toollabz Editorial
Product editor | Last reviewed July 18, 2026
See methodology and editorial policy.