Category
Healthy
Health · Body measurement
BMI
BMI
calculator
Your body mass index in metric or imperial units, with an honest healthy-weight range for your height. It updates the instant you change a number — and none of it leaves your device.
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Healthy range
57–76 kg
What body mass index measures
Body mass index is a single number that relates your weight to your height. It was designed as a quick population-level screen, not a body-fat measurement — but for most adults it gives a reasonable first read on whether weight sits in a healthy band for height.
The formula
BMI = weight (kg) ÷ height (m)²
Worked example
Someone who weighs 75 kg and stands 175 cm (1.75 m) tall:
75 kg at 1.75 m
1.75 × 1.75 = 3.0625
75 ÷ 3.0625 = 24.5 → Healthy
75 ÷ 3.0625 = 24.5 → Healthy
The categories
These are the standard World Health Organization bands for adults:
- Under 18.5 — underweight
- 18.5 to 24.9 — healthy weight
- 25 to 29.9 — overweight
- 30 and above — obese
Imperial units
If you think in pounds and feet, the arithmetic is the same idea with a conversion factor baked in:
Imperial formula
BMI = 703 × weight (lb) ÷ height (in)²
Where BMI falls short
Because it only knows your height and weight, BMI can't tell muscle from fat. A lean, heavily built athlete can land in the "overweight" band while carrying very little fat, and BMI doesn't account for age, sex, or where fat is stored — which matters more for health than the raw number. It also isn't valid for children, who use age- and sex-specific percentile charts instead. Read it as a starting point, not a verdict.
Your healthy weight range
The band works in reverse, too. Multiply the healthy BMI range of 18.5 to 24.9 by the square of your height in metres to get a target weight range. At 1.75 m that's roughly 57 to 76 kg — the calculator above shows the range for your own height as you type.
Common questions
BMI FAQ
BMI is your weight in kilograms divided by the square of your height in metres. For 75 kg at 1.75 m: 75 ÷ (1.75 × 1.75) = 24.5. In imperial units, BMI = 703 × pounds ÷ inches².
For most adults, a BMI from 18.5 to 24.9 is classed as healthy. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or above is obese.
BMI is a rough screening tool, not a diagnosis. It uses only height and weight, so it can't tell muscle from fat and doesn't account for build, age, or where fat is stored. Very muscular people often read as overweight despite low body fat.
Multiply the BMI range 18.5 to 24.9 by the square of your height in metres. At 1.75 m that is roughly 57 to 76 kg. This calculator shows the range for your height automatically.
Not directly. Children and teenagers use age- and sex-specific percentile charts, and athletes with high muscle mass can be misread. Treat this as a general adult guide and check anything important with a professional.