BMI Calculator

BMI is a screening figure, not a diagnosis. It uses only height and weight, so it cannot tell muscle from fat — a very muscular person can register as overweight while carrying little fat. It is also less reliable for people under 18, over 65, pregnant, or with a limb difference.

Categories are the World Health Organization adult thresholds, verified 5 August 2026. NICE advises lower thresholds for people of South Asian, Chinese, Black African, African-Caribbean and Middle Eastern family background, because health risks appear at a lower BMI — see the NHS BMI tool for guidance that accounts for this. If you have any concern about your weight, a GP is the right place to take it.