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BMI calculator

A quick adult body mass index estimate.

Adults 20+ only. A screening measure, not a diagnosis.

What is this tool?

Calculate the relationship between adult body weight and height using the BMI formula. This page provides a screening calculation and explains its limits. It is not a body-fat measurement or a personalized assessment of fitness.

How to use it

  1. Read the input labels and limits below, then choose the operation that matches your task.
  2. Enter weight in kilograms.
  3. Enter height in centimetres, checking that metres were not entered by mistake.
  4. Calculate and read both the number and the limitations shown with it.
  5. Check the result against the worked example or original file before copying, downloading or using it elsewhere.

Worked example

A height of 1.65 metres should be entered as 165 centimetres. Entering 1.65 in a centimetre field changes the scale dramatically. Accurate units are essential before interpreting any calculated category.

Questions & limits

BMI = weight in kilograms ÷ height in metres squared. Standard adult categories: below 18.5, underweight; 18.5–24.9, healthy weight; 25–29.9, overweight; 30 or above, obesity. BMI does not directly measure body fat and can misclassify muscular people. Not suitable for children or assessing pregnancy.

CDC: adult BMI categories

Which units does this calculator accept?

Enter weight in kilograms and height in centimetres. The result is an adult screening estimate. It does not directly measure body fat or determine an individual’s health.

Can two people with the same BMI have different health?

Yes. BMI does not distinguish muscle from fat or describe fat distribution, medical history, fitness or individual nutritional needs. It should not be used alone to judge health.

Using estimates responsibly

These calculations depend on the measurements and assumptions you enter. Check the units and avoid interpreting a single number as a complete assessment. A result can be mathematically correct while still being unsuitable for your personal situation. The page explains the equation and its scope so you can understand what was calculated. It does not diagnose a condition, recommend treatment or replace individual advice. If the result will inform a health decision, discuss your circumstances with a qualified professional.

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Features & limits

Uses weight in kilograms and height in centimetres. Inputs allow weight up to 700 kg and height from 50–300 cm. Standard adult categories apply to adults aged 20 and over. BMI is a screening estimate, not a diagnosis or a direct measurement of body fat.

This tool runs in a modern browser with JavaScript enabled. It processes the values or files you enter on your device. Loading the site still makes hosting requests. The separate contact form sends messages to the administrator; it is not part of tool processing. Keep an original copy and inspect any exported result before relying on it.

Frequently asked questions

Can two people with the same BMI have different health?

Yes. BMI does not distinguish muscle from fat or describe fat distribution, medical history, fitness or individual nutritional needs. It should not be used alone to judge health.

What can I use bmi calculator for?

Calculate the relationship between adult body weight and height using the BMI formula. This page provides a screening calculation and explains its limits. It is not a body-fat measurement or a personalized assessment of fitness.

What are this tool’s limits?

Uses weight in kilograms and height in centimetres. Inputs allow weight up to 700 kg and height from 50–300 cm. Standard adult categories apply to adults aged 20 and over. BMI is a screening estimate, not a diagnosis or a direct measurement of body fat.

Can I try a worked example?

A height of 1.65 metres should be entered as 165 centimetres. Entering 1.65 in a centimetre field changes the scale dramatically. Accurate units are essential before interpreting any calculated category.

Do I need an account or upload my input?

No tool account is required. Processing takes place in your browser; your tool input is not sent to the contact inbox. Use a trusted device, keep your originals and avoid including passwords or private credentials in examples.

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