BMI Calculator

Body mass index (BMI) compares your weight with your height. It is a quick screening number that doctors and public health bodies use to see whether weight may be affecting health risk. It is not a diagnosis.

Height in
Weight in
Results update as you type.

Your BMI

23.5

Normal weight

Healthy range for your height (WHO)
53.5 – 72 kg
Using Asian Indian cut-offs
Overweighthealthy range 52 – 66.2 kg

For adults aged 18 and over. Not for children, pregnancy, or very muscular builds.

About this calculator

Enter height and weight in whichever units you use. You get your BMI, the WHO category, the weight range that falls in the healthy band for your height, and the category under the lower cut-offs recommended for adults of Asian Indian origin.

How to use it

  1. Choose centimetres or feet and inches, and enter your height.
  2. Choose kilograms or pounds, and enter your weight.
  3. Read your BMI and both sets of categories.

The formula

BMI = weight in kg ÷ (height in m)²
weight
body weight in kilograms (1 lb = 0.45359237 kg)
height
height in metres (1 inch = 0.0254 m)

Worked example

Height 165 cm, weight 72 kg

  1. Height = 1.65 m, so height² = 2.7225.
  2. BMI = 72 ÷ 2.7225 = 26.4.
  3. WHO category: overweight (25 to 29.9). Under the Asian Indian cut-offs it falls in the obese range (25 and above).
  4. The WHO healthy range for 1.65 m is 50.4 to 67.8 kg.

What the result means

WHO adult categories are: under 18.5 underweight, 18.5 to 24.9 normal, 25 to 29.9 overweight, and 30 or more obese.

Research has shown that many South Asian adults carry more body fat and face higher risk of diabetes and heart disease at the same BMI as other groups. Indian consensus guidelines therefore use lower cut-offs: 23 to 24.9 is overweight and 25 or more is obese. Both views are shown so you can see the difference.

A BMI outside the healthy band is a reason to talk to a doctor, who will look at waist size, blood pressure, blood sugar and other measures before drawing conclusions.

Assumptions

  • You are an adult aged 18 or over.
  • Height is measured without shoes and weight with light clothing.

Limitations

  • BMI cannot tell fat from muscle. Athletes and very muscular people can show a high BMI while having little body fat.
  • It does not show where fat is carried. Fat around the waist carries more risk than the same BMI suggests.
  • Children and teenagers need age- and sex-specific growth charts, not these adult categories.
  • It is not suitable during pregnancy.

Frequently asked questions

What is a normal BMI for Indians?

Under the Indian consensus guidelines, a BMI from 18 to 22.9 is normal for adults. The WHO range of 18.5 to 24.9 is the international standard.

Is BMI accurate?

It is accurate as arithmetic but limited as a health measure, because it ignores muscle, bone and where fat sits. It is a starting point for a conversation with a doctor, not a verdict.

Can I use this BMI calculator for my child?

No. Children’s BMI must be compared against growth charts for their age and sex. Please ask a paediatrician.

How is BMI calculated in pounds and inches?

Multiply weight in pounds by 703 and divide by height in inches squared. This calculator converts to kilograms and metres first, which gives the same result.

Not medical advice. This calculator is a general screening tool and cannot diagnose any condition. Results are estimates. Please talk to a doctor or a qualified health professional about your health and before making changes to diet, exercise or treatment.

Last reviewed on 29 September 2026. Found a mistake? Tell us.