BMI Calculator

Free BMI calculator: enter your weight and height in kg/cm or lb/ft/in to get your body mass index, your category, your healthy weight range and how much to gain or lose. WHO or Asian cut-offs, a gauge, and saved measurements with a BMI-over-time chart.

Mix units freely: type weight in kg or lb and height in cm or ft + in, in any combination — the other fields fill in as you type.

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Every field stays in step with its twin. Adults 20 and over only; see the notes below.

Enter your weight and height to see your BMI — or try an example:

How BMI is calculated

Body Mass Index is your weight divided by your height squared:

BMI = weight (kg) ÷ height (m)²  or  703 × weight (lb) ÷ height (in)²

For example, 65.8 kg at 182.9 cm is 65.8 ÷ (1.829 × 1.829) = 19.7, in the normal range.

BMI categories for adults

The WHO standard cut-offs are used by most countries. The WHO Asia-Pacific cut-offs (overweight from 23, obese from 27.5) reflect the higher health risk at lower BMI in many Asian populations. Switch the BMI scale above to use them.

Important notes on BMI

BMI is a general screening tool, not a diagnosis. It assumes a “normal” proportion of weight to height for people of average build and activity, which has some limits:

  • It does not tell muscle from fat: athletes and bodybuilders can have a high BMI with low body fat.
  • Body shape, bone structure, age, sex and ethnicity all change what a healthy weight looks like.
  • It does not show where fat is carried; a larger waist measurement is a separate risk marker.
  • Children and teens (2–19) are judged with BMI-for-age percentiles, not these cut-offs: use a growth chart such as the CDC child and teen BMI calculator.

BMI is still popular because it is the simplest index to compute and has decades of research behind it. Talk to a doctor or dietitian before starting a new diet or fitness plan. What is BMI? · BMI chart · BMI formula · Health tips

Is my data private?

Yes. Your numbers and saved measurements stay in this browser. Nothing is uploaded unless you copy a link and share it yourself.

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