BMI Calculator — Check Your Body Mass Index

Divide your weight in kilograms by your height in metres squared. For example, at 70 kg and 175 cm: 70 ÷ (1.75 × 1.75) = 22.9, a healthy weight. The calculator above does this instantly from kg and cm inputs.

Choose the Metric tab and enter your weight in kilograms and height in centimetres. The metric BMI formula is weight (kg) ÷ height² (m²) — for example, 70 kg at 1.75 m gives BMI 22.9, the middle of the healthy range.

A BMI between 18.5 and 24.9 is considered healthy for most adults. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or above falls in the obese range.

Not entirely. BMI cannot tell muscle from fat, so very muscular people can score 'overweight' while being perfectly healthy. It's a useful general screening tool, not a diagnosis — for body composition ask a professional.

BMI = weight in kilograms divided by height in metres squared (kg/m²). In imperial units the same result comes from 703 × pounds / inches².

The BMI categories are the same for adult men and women. Children and teenagers use age- and sex-specific percentile charts instead of the adult ranges.

BMI = weight (kg) ÷ height (m)². At 80 kg and 180 cm: 80 ÷ (1.80 × 1.80) = 24.7, a healthy weight. The calculator above accepts kg and cm directly.

Yes. Enter your weight in kg, then convert your height: multiply feet by 30.48 and inches by 2.54. For example, 5′10″ is (5 × 30.48) + (10 × 2.54) ≈ 178 cm, so type 178 in the height box.

Absolutely. Switch the unit toggle to imperial and enter stones and pounds (e.g. 11 st 2 lb) with height in feet and inches. BMI comes out identical whichever system you use.

Mixing units is fine: enter your weight in kilograms and your height in feet and inches above — the calculator converts your height to metres internally. If you prefer the formula by hand, BMI = kg ÷ (m)², so convert your height to metres first (1 foot = 0.3048 m, so 5 ft 7 in = 1.70 m).