BMI Calculator

Your BMI: 22.9
Category: Healthy weight
Healthy weight for your height, from: 56.66 kg
Up to: 76.26 kg

Underweight below 18.5
Healthy weight 18.5 to 24.9
Overweight 25 to 29.9
Obese 30 to 39.9
Severely obese 40 or more

What it does

Body mass index (BMI) compares your weight with your height to give a quick idea of whether you're a healthy weight. Enter both, in metric, feet and stones, or feet and pounds, to see your BMI, which range it falls in, and the healthy weight range for your height.

How to use it

Height: Your height without shoes. Switch between cm and feet and inches in the Units box.
Weight: Your weight, ideally first thing in the morning. Kilograms, stones and pounds, or pounds.
Family background: Asian includes South Asian and Chinese. People from these family backgrounds have a higher risk of health problems at a lower BMI, so the NHS and NICE use lower thresholds for them.

Common uses

Checking whether your weight is in the healthy range.
Setting a target weight for your height.
Working out how many calories you need.
Counting the alcohol units in your drinks. Try the Alcohol Units Calculator (UK)

The formula

BMI = weight in kg ÷ (height in metres × height in metres)

Where:

kg/m²: BMI's unit, usually left off

Feet, inches, stones and pounds are converted to metres and kilograms first.

Worked example

For a height of 175 cm and a weight of 70 kg:

Height in metres, squared: 1.75 × 1.75 = 3.0625
BMI: 70 ÷ 3.0625 = 22.9

That's in the Healthy weight range. For this height, a healthy weight is 56.66 kg to 76.26 kg.

Questions people ask

Is BMI accurate for everyone?

No. It's a quick screening measure for adults. It can't tell muscle from fat, so very muscular people can show as overweight, and it isn't used during pregnancy. Children and teenagers need a BMI centile calculator that allows for age and sex. Talk to a GP if you're worried about your weight.

Why are there lower thresholds for some backgrounds?

People of South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean family background have a higher risk of conditions such as type 2 diabetes at a lower BMI. NICE guidance uses 23 for overweight and 27.5 for obesity for these groups, instead of 25 and 30.

What else should I check besides BMI?

Waist size matters too, because fat around the middle carries more health risk. A common check is that your waist should be less than half your height.

Last checked 25 October 2026