BMI Explained: What Your Body Mass Index Really Means
Understand BMI: how it's calculated, what the numbers mean, its limitations, and how to use it alongside other health metrics.
common.whatIsBMI
Body Mass Index (BMI) is a screening tool that estimates body fat based on height and weight. It was developed in the early 19th century by Belgian mathematician Adolphe Quetelet.
common.common.learnMoreFrom common.common.who common.common.and common.common.cdc
common.quickFacts
- • Used by health professionals worldwide as a screening tool
- • Does not directly measure body fat
- • Correlates with health risks but doesn't diagnose conditions
- • Same formula applies to adults 20+ years old
common.howToCalculateBMI
common.metricFormula
BMI = weight (kg) / height² (m²)
common.imperialFormula
BMI = (weight (lbs) × 703) / height² (in²)
common.exampleCalculation
Person 70 kg, 175 cm tall
common.step 1: height squared = 1.75 × 1.75 = 3.0625
common.step 2: BMI = 70 / 3.0625 = 22.9
Result: Normal weight (BMI: 22.9)
common.bmiCategories
| common.category | common.bmiRange | common.healthRisk |
|---|---|---|
| common.underweight | common.below 18.5 | common.increased |
| common.normal | 18.5 - 24.9 | common.lowest |
| common.overweight | 25.0 - 29.9 | common.increased |
| common.obese | 30.0 common.andAbove | common.highToVeryHigh |
common.note: BMI ranges are the same internationallyfor children, BMI uses percentiles by age and gender
common.limitationsOfBMI
common.usefulScreening
common.doesNotDistinguish
common.athletesHighBMI
common.doesNotMeasureFatLocation
common.bellyFatRiskier
common.ageDifferences
common.optimalBMIHigher
common.ethnicDifferences
common.asianPopulationsRisk
common.alternativeMetrics
common.completeHealthPicture
common.waistCircumference
Men: Above 40 inches (102 cm) | Women: Above 35 inches (88 cm) indicates increased health risk.
common.waistHeightRatio
Ratio above 0.5 indicates increased health risk. Simple and more accurate than BMI alone.
common.bodyFatPercentage
Men: 10-20% | Women: 18-28% is considered healthy. Can be measured with bioelectrical impedance or skinfold calipers.
common.waistToHipRatio
Men: Below 0.90 | Women: Below 0.85 indicates lower health risk.
common.tryOurCalculator
BMI →common.continueLearning
About the Author
Written by PercentHub Team
Expert team specializing in financial and health calculations
⚠️Disclaimer
Health-related calculations (such as BMI) are general indicators and should not replace professional medical advice. Please consult a healthcare professional for personalized guidance.