How is BMI calculated?

BMI is your weight in kilograms divided by your height in metres squared. For example, 70 kg at 1.75 m gives 70 ÷ 1.75² = 22.9. In pounds and inches, the calculator converts for you.

What is a healthy BMI?

For adults, the World Health Organization calls 18.5–24.9 a healthy weight, 25–29.9 overweight and 30 or more obesity. For people of Asian descent, WHO suggests action from 23 and 27.5, because health risks start at lower BMIs – tick the option to use those cut-offs.

It's a quick screening number, not a diagnosis. It can't tell muscle from fat, so athletes may score high, and it doesn't show where fat sits. Waist-to-height ratio and body fat estimates add useful context; a doctor can give the full picture.

How many calories do I need?

The calculator estimates your resting energy use (BMR) with the Mifflin–St Jeor equation and multiplies it by your activity level. Eating about 500 kcal a day less than that loses roughly 0.5 kg (1 lb) a week – it never suggests going below your BMR.

BMI Calculator – with Calories, Body Fat and Healthy Weight

Work out your body mass index in metric or imperial units, see your healthy weight range, daily calories (BMR and TDEE) and body fat percentage. Free, private, nothing is uploaded.

Your measurements stay on this device – nothing is sent anywhere.

Height (cm)Weight (kg)AgeActivity

Use the Asian BMI cut-offs (WHO Asia-Pacific)

Enter your height and weight to see your BMI.

Body fat (optional)

Waist (cm)Neck (cm)Hips (cm)

Measure the waist at the navel (men) or narrowest point (women), the neck below the larynx, and the hips at the widest point.

For adults 20 and over. BMI doesn't tell muscle from fat and isn't a diagnosis – talk to a doctor about your health.

A free BMI calculator that also answers the next questions. Enter your height and weight in centimetres and kilograms or feet, inches and pounds to see your body mass index on the WHO scale, with the option of the lower cut-offs WHO recommends for Asian populations, and the weight range that counts as healthy for your height. Add your age, sex and activity level to get your resting energy use (Mifflin–St Jeor) and the calories you need per day to keep, lose or gain weight, and your waist, neck and hip measurements for an estimate of body fat and your waist-to-height ratio. Your numbers are remembered only on this device.

BMI Calculator – with Calories, Body Fat and Healthy Weight

Body fat (optional)

Frequently asked questions

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