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BMI Calculator

Calculate adult body mass index with US or metric measurements.

Your numbers

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Updates as you type
Body mass index
23.6748kg/m²

Calculated from your inputs · rounded for display

Adult BMI categoryHealthy weight
Weight74.8427kg
Height177.8cm

For adults 20+. BMI is a screening measure and does not measure body fat or diagnose health. It may be less informative for athletes and during pregnancy.

Your calculation, step by step

No black boxes
  1. Weight = 74.842741 kg; height = 1.778 m.
  2. BMI = 74.842741 ÷ 1.778² = 23.674792.

How to use this calculator

  1. Enter your own values in the labeled fields. Check the units and assumptions before comparing results. Only the fields needed for your selected calculation mode are shown.
  2. Your answer updates automatically. Review the calculation steps to see exactly how it was calculated.
  3. Copy, share, save, or download your result. Saved inputs stay on this device.

How the calculation works

BMI = weight (kg) / height (m)²

BMI relates body mass to height and is commonly used as an adult screening measure. It cannot distinguish muscle from fat, measure fat distribution, or explain individual health. Adult cutoffs differ from the age-specific approach used for children. Use this tool only for adults 20 and older and discuss health decisions with a qualified professional.

A worked example

At 75 kg and 1.80 m, BMI = 75 ÷ 1.80² = 23.15 kg/m².

Reading your result

Use the main result together with its units and supporting figures. Display values are rounded; calculations keep their underlying precision. A change in inputs or assumptions can change the answer. Compare the step-by-step working with your intended use before relying on an estimate.

Frequently asked questions

Does BMI measure body fat?

No. It uses only weight and height and does not directly measure body composition.

Can children use this calculator?

No. Children and teens require age- and sex-specific growth references.

Sources & methodology

CDC: BMI calculation and limitations ↗

Formula review: October 24, 2026. Read our methodology.