BMI Calculator
Calculate your Body Mass Index (BMI) with imperial or metric units. See your BMI category, visual scale, and healthy weight range.
Your Measurements
Your BMI
24.4
Normal
Healthy Weight Range
128.9 - 173.5 lbs
How to Use BMI Calculator
- 1
Choose units
Select imperial (lbs, ft/in) or metric (kg, cm).
- 2
Enter weight
Enter your weight in the selected unit.
- 3
Enter height
Enter your height in the selected unit.
- 4
View results
See your BMI value, category, visual scale, and healthy weight range.
Frequently Asked Questions
Related Tools
What BMI Actually Measures — and What It Doesn't
BMI was invented in the 1830s by Belgian mathematician Adolphe Quetelet as a population-level statistical tool, not a clinical diagnostic. The formula — weight in kilograms divided by height in meters squared — produces a single number that correlates with body fat at the population level. But for individuals, it can be misleading. A 6-foot muscular athlete at 220 lbs has a BMI of 29.8 (overweight), while a sedentary person at the same height and weight with high body fat percentage gets the same score.
The BMI Categories and Their Origins
The WHO categories (underweight below 18.5, normal 18.5-24.9, overweight 25-29.9, obese 30+) were established based on epidemiological studies linking BMI ranges to mortality risk. The "normal" range corresponds to the lowest all-cause mortality in large population studies. However, these cutoffs were derived primarily from European populations — the WHO recommends different thresholds for Asian populations, where metabolic risks increase at lower BMI values (overweight at 23, obese at 25).
Better Alternatives to BMI
Waist circumference is a stronger predictor of cardiovascular disease than BMI because it correlates with visceral fat — the metabolically dangerous fat around organs. A waist-to-height ratio above 0.5 indicates elevated risk regardless of BMI. Body fat percentage, measured via DEXA scan or bioelectrical impedance, gives the most direct assessment. For clinical purposes, BMI is a screening tool that should prompt further evaluation, not a diagnosis.