BMI Calculator
BMI (Body Mass Index) is a screening tool based on height and weight. Enter your measurements to see your category.
Result
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Enter height and weight above to see your BMI.
BMI is a population-level screening tool and can misclassify very muscular people (common in strength sports). Consider it one data point, not a diagnosis.
Categories
| Category | BMI |
|---|---|
| Underweight | < 18.5 |
| Normal | 18.5 – 24.9 |
| Overweight | 25.0 – 29.9 |
| Obese (Class I) | 30.0 – 34.9 |
| Obese (Class II) | 35.0 – 39.9 |
| Obese (Class III) | 40.0+ |
Understanding Your BMI
Body Mass Index is a ratio of weight to height — kilograms divided by height in meters squared. It was designed as a population-level screening tool, not a precise individual health measurement. Across large groups, elevated BMI correlates with increased risk for metabolic disease, cardiovascular disease, and all-cause mortality. For any given individual, particularly strength athletes, the picture is more complicated.
Reading the categories
The WHO ranges give context for where you fall relative to population norms. "Normal weight" (18.5–24.9) is associated with the lowest average health risk at the population level. The "Overweight" and "Obese" categories carry statistically elevated risk — but those are group averages, not individual diagnoses.
Why BMI misclassifies strength athletes
BMI cannot distinguish muscle from fat. Skeletal muscle is significantly denser than adipose tissue, so a highly trained athlete can carry far more lean mass than a sedentary person of the same height — pushing their BMI into "overweight" or "obese" territory despite having low body fat. A 220 lb powerlifter at 6' and 12% body fat has a BMI of about 29.8 (technically "overweight") — but they are not metabolically comparable to someone else at that BMI who is largely sedentary.
The reverse also occurs: a sedentary person with low muscle mass can fall in the "normal" range while carrying a high body fat percentage and very little lean tissue. BMI doesn't flag this either.
A more complete picture
Pair your BMI with a body fat estimate — DEXA scan, calipers, or a BIA scale — and you'll have a far more informative view of your body composition. BMI is a useful starting point and worth knowing, but it's one data point in a larger set. For strength athletes especially, it should never be the only number you rely on.
Read more in the Reading Your BMI guide.