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BMI Calculator

Calculate BMI from weight in kg and height in cm. Understand the displayed adult reference label and why BMI alone cannot assess an individual's health.

This metric calculator divides weight in kilograms by squared height in metres. It displays BMI to one decimal place and a broad adult reference label. BMI is a screening measure rather than a diagnosis and does not directly measure body fat or body composition.

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  1. 1Enter details
  2. 2View result
Body Mass IndexLive
Body Mass Index22.9Normal weight

BMI uses adult reference categories and does not measure body composition.

Your input stays on this device for this operation. We don’t upload or store it.

About BMI Calculator

This metric calculator divides weight in kilograms by squared height in metres. It displays BMI to one decimal place and a broad adult reference label. BMI is a screening measure rather than a diagnosis and does not directly measure body fat or body composition.

Metric formula

Uses kg divided by height in metres squared.

Live numeric output

Displays one decimal place and provides a copyable result.

Adult reference labels

Uses thresholds of 18.5, 25 and 30, with the category based on the unrounded calculation.

How to use BMI Calculator

  1. 1

    Check the units

    Prepare weight in kilograms and height in centimetres. Convert pounds or feet separately before entering them.

  2. 2

    Enter positive measurements

    Fill Weight (kg) and Height (cm). The numeric result updates automatically.

  3. 3

    Read the scope

    Treat the category as a broad adult reference, alongside the limitations below. This tool supplies no personal treatment or weight-change advice.

Formats and practical limits

Input: positive finite kg and cm values. Output: BMI rounded to one decimal and a broad adult-reference label, with copyable text.

  • No child percentiles, pregnancy assessment, ethnicity-specific thresholds, body-composition measurement or diagnosis. Do not use this page to make personal health decisions.
  • The tool accepts positive numbers without clinical plausibility ranges. Verify units and measurements; the displayed 'Normal weight' label is a software reference label, not an individual health conclusion.

Practical example

For a formula demonstration, 70 kg and 175 cm give 70 ÷ 1.75² = 22.857…, displayed as 22.9. This example makes no health recommendation.

Further reading

Frequently Asked Questions

3 answers
Is this suitable for children?

No. Children and teenagers need age- and sex-specific interpretation. CDC's adult calculator covers ages 20 and older, while NHS adult guidance starts at 18; follow the appropriate clinical service rather than using this page for a child.

Does the label diagnose my health?

No. BMI alone cannot assess individual health or distinguish muscle from fat. A qualified clinician can interpret measurements with other relevant information.

Why can a rounded value appear beside a different category?

The display rounds BMI to one decimal, but the label uses the unrounded value. A value just below 25 can display as 25.0 while retaining the lower reference label.

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