BMI Calculator UK (metric, stones & pounds)
Enter your height and weight in metric or imperial to see your BMI and which NHS weight range it falls in.
For general information only, not medical advice. Speak to your GP, midwife or a health professional about your own health.
How it works
BMI = weight in kg ÷ (height in metres)². For example, 70 kg and 1.75 m gives 70 ÷ 3.06 = 22.9.
NHS adult ranges: under 18.5 underweight, 18.5–24.9 healthy, 25–29.9 overweight, 30–39.9 obese, 40+ severely obese. People of Black, Asian and some other ethnic backgrounds have a higher risk at lower BMIs (from 23).
BMI doesn't tell muscle from fat, so very muscular people can score high. It's a screening guide, not a diagnosis.
Frequently asked questions
What is a healthy BMI?+
18.5 to 24.9 for most adults.
Is BMI accurate for children?+
No. Children's BMI is compared with age and sex charts. Use the NHS child BMI calculator for under-18s.