Gauritanaya

BMI calculator

Get your BMI, the category that applies to your background, and a healthy weight range for your height.

Runs entirely in your browser. Nothing you type is sent anywhere.

Height
cm
Weight
kg
years

Some guidelines use lower thresholds for people from certain backgrounds. Choose the one that fits your family background, not where you live.

Waist (optional)
cm

Adds your waist-to-height ratio.

Your BMI—

Ranges used
—
Healthy weight for your height
—

For general wellness only. These results are estimates from published formulas and guidelines, not a diagnosis or medical advice. They may not suit pregnancy, children, older adults, athletes or people with health conditions. Talk to a qualified health professional about your health. In an emergency, call your local emergency number.

How to use the BMI calculator

BMI is weight in kilograms divided by the square of height in metres. Adults are compared with the WHO ranges. NICE (the UK health guidance body) recommends lower thresholds for people of South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean family background: overweight from 23 and obesity from 27.5, with each obesity class 2.5 lower. Waist-to-height ratio uses the NICE bands: 0.4–0.49 healthy, 0.5–0.59 increased, 0.6 or more high.

  1. Choose metric or imperial units.
  2. Enter your height and weight, and your age.
  3. Optionally choose your family background and add your waist measurement.
  4. Read your BMI, the ranges used and the healthy weight range for your height.

Understanding your result

Your category depends on the ranges used: the WHO ranges for most adults, or the lower NICE thresholds if you chose one of the listed family backgrounds. A result in the overweight or obesity range is a prompt to look at your waist size and talk to a health professional, not a diagnosis. The healthy weight range shows the weights that would give a healthy BMI at your height.

Sources

Sources checked on 9 October 2026. Formulas and thresholds are used as published; the wording on this page is our own.

Questions

Why does my background change the result?
Large studies found that people from some backgrounds face higher health risks at a lower BMI. NICE therefore lowers the thresholds for South Asian, Chinese, other Asian, Middle Eastern, Black African and African-Caribbean adults. If you don’t choose a background, the WHO ranges are used.
Which cut-offs does India use?
An Indian consensus statement (Misra et al., 2009) uses 23–24.9 for overweight and 25 or more for obesity in Asian Indian adults. This tool shows the NICE thresholds, which start obesity at 27.5, so the two can give different labels between 25 and 27.4.
Can children and teenagers use this?
They can see their BMI number, but under 18 it must be compared with age- and sex-specific growth charts, so this tool doesn’t give a category. A child’s doctor or nurse can plot it for you.
Does BMI apply during pregnancy?
No. Weight gain in pregnancy is assessed against your pre-pregnancy BMI, so the category is switched off when you tick “I’m pregnant”.
Why add my waist?
BMI can’t tell muscle from fat or show where fat is stored. NICE recommends also checking waist-to-height ratio. Keeping your waist under half your height is the general guide, and NICE says the same 0.5 boundary applies to all ethnicities and sexes.
Is this a diagnosis?
No. It compares your numbers with published ranges for general wellness. Only a qualified health professional can assess your health, taking your history and other tests into account.

Related tools