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BMI Calculator

Calculate adult BMI from height and weight in metric or imperial units, including feet and inches.

Inputs stay on your device No sign-up Free to use
How this works

The tool runs in this browser. Your file or text is not uploaded to UseFreeTools. Check this tool's limits for anything it may save on your device.

Privacy details

Showing an example. Edit to see your own.

Used with feet. Enter the remaining whole inches from 0 to 11.

Processed in your browser. Your inputs stay on this device.

How to use BMI Calculator

  1. Enter your age. This calculator uses the adult categories for people age 20 or older.
  2. Enter height and weight. Choose cm, inches, or feet and inches for height, and kg or pounds for weight.
  3. The result, adult screening category and limits update as you change the fields. Read them before using the figure for any decision.

Example: BMI Calculator

Work out the adult BMI for a person who is 170 cm tall and weighs 70 kg.

You add
Age 30 years; height 170 cm; weight 70 kg.
You get
BMI is 24.2 because 70 ÷ (1.70 × 1.70) is about 24.22. The unrounded value is in the adult healthy-weight screening category.

Options

Units
Choose a unit beside each measurement. Centimeters, inches and feet are converted to meters, and pounds to kilograms, before the same BMI formula is used.
Adult categories
The category uses the unrounded BMI. The displayed number is rounded to one decimal, so a result near a boundary may look like the next category's starting number.

Supported inputs and limits

This page is for adults age 20 or older. It accepts height equivalent to 0.8–2.5 m and weight equivalent to 20–500 kg. In feet + inches, enter whole feet and the remaining whole inches from 0 to 11. BMI uses only height and weight; it cannot assess body composition, medical history or health on its own. It does not use child or teen growth charts. The result is a screening calculation, not a diagnosis or medical advice. Ask a qualified health professional about personal health questions.

Where your input is processed

This tool processes your input in this browser. Your text and files are not uploaded to UseFreeTools. Check this tool's limits for anything it may save on your device.

Sources and assumptions

Checked 2026-09-28. BMI is weight in kilograms divided by height in meters squared. This page converts pounds using 0.45359237 kg per pound, inches using 0.0254 m per inch, and feet at 0.3048 m per foot with 12 inches per foot. The CDC adult cutoffs are below 18.5, 18.5 to below 25, 25 to below 30 and 30 or above. The CDC describes BMI as a screening measure rather than a diagnosis. The tool makes no treatment or weight-loss recommendation.

CDC, Adult BMI Calculator (reviewed 2024; checked 2026-09-28)

Questions about BMI Calculator

Does BMI diagnose whether I am healthy?

No. BMI is a screening measure. Health assessment can also need medical history, an examination and other measurements. A clinician can put the figure in context.

Can I enter pounds, feet and inches?

Yes. Choose lb for weight. For height, choose in for whole inches, or ft + in to enter feet and the remaining inches in separate boxes. For example, 5 ft 6 in is 66 inches.

Why does my category seem different near a cutoff?

The category is chosen from the unrounded BMI, while the large result shows one decimal. A value just below a boundary can round to that boundary on screen.

Can I use this for a child or teenager?

No. This page uses adult categories for ages 20 and older. Children and teenagers need age- and sex-specific growth charts.

Project manager: Tony Hines · Content updated 29 September 2026 · Report a problem

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