Health
BMI Calculator
Enter your height and weight in imperial or metric units. We compute Body Mass Index, the standard category, and the healthy weight range that corresponds to BMI 18.5–25 at your height.
Units
Standard BMI scale
- < 18.5 — Underweight
- 18.5–24.9 — Normal weight
- 25.0–29.9 — Overweight
- 30.0–34.9 — Obese (class I)
- 35.0–39.9 — Obese (class II)
- ≥ 40.0 — Obese (class III)
Overweight
25.8
180 lb · 5′10″
BMI is a screening estimate from height and weight. It doesn't distinguish muscle from fat, doesn't adjust for age or frame, and isn't a diagnosis on its own. Use it as a starting point, not a verdict.
Examples
5′10″, 180 lb
BMI ≈ 25.8 · Overweight
5′6″, 140 lb
BMI ≈ 22.6 · Normal weight
178 cm, 70 kg
BMI ≈ 22.1 · Normal weight
165 cm, 90 kg
BMI ≈ 33.1 · Obese (class I)
How it works
Body Mass Index is the ratio of weight to height squared. We convert both inputs to metric, compute the index, and look up the standard category band.
BMI · kg / m²
Imperial form · 703 × lb / in²
The healthy weight range we report is the kg band corresponding to BMI 18.5–25 at your specific height — handy if you want a target range rather than a single number.
Estimate, not medical advice. BMI is a screening tool. It doesn't distinguish muscle from fat, doesn't apply to children, teens, or pregnant women, and isn't a diagnosis. If you have a medical condition, an eating disorder, or any nutrition concern, talk to a qualified healthcare professional rather than relying on a calculator.
Frequently asked questions
Body Mass Index is a number computed from your height and weight: BMI = kg / m². It's used as a quick screening tool to flag whether someone's weight falls in a typical range for their height. It is not a diagnosis, and it doesn't measure body composition.
The World Health Organization scale: under 18.5 underweight, 18.5–24.9 normal weight, 25–29.9 overweight, 30–34.9 obese class I, 35–39.9 obese class II, 40 or above obese class III. The same scale applies to adult men and women, though clinical interpretation varies by population.
Take your height in metres, square it, then multiply by 18.5 and 25 — that's the kg range corresponding to BMI 18.5–25. We compute that range for you in either pounds or kilograms. It's where most adults sit when their weight is described as “healthy” at their height.
BMI doesn't distinguish muscle from fat, doesn't account for frame size, and was originally derived from northern European populations. Athletes and very muscular people can land in the “overweight” or “obese” bands while having low body fat. Older adults can have a “normal” BMI with high body fat (sarcopenic obesity). Use BMI as one signal among several, not as a verdict.
No. BMI for children and teens uses age- and sex-specific percentile charts, not the adult scale. BMI is also not a useful screening tool during pregnancy. This calculator targets non-pregnant adults.
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