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Calculators

BMI Calculator

Body Mass Index is a quick screening number. Get yours, your healthy weight range, and context for reading it properly.

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About this tool

BMI is weight in kilograms divided by height in metres squared. The World Health Organization uses 18.5-24.9 as the healthy range for adults, 25-29.9 as overweight and 30+ as obesity. It is quick and correlates with health outcomes across populations.

It is also blunt. It cannot distinguish muscle from fat, does not account for where fat is stored, and thresholds are lower for some Asian populations. A muscular person can be "overweight" by BMI while very lean; someone with normal BMI can carry excess abdominal fat. That is why we pair BMI with waist-to-height ratio and body fat.

How to read your result

Under 18.5

Underweight.

18.5-24.9

Healthy range.

25-29.9

Overweight range.

30+

Obesity range.

Frequently asked questions

Is BMI accurate for athletes?
Often not. Muscle is dense, so muscular people read high. Use waist-to-height ratio or body fat instead.
Does BMI apply to children?
No - children use age- and sex-specific percentile charts. This tool is for adults 18+.

This tool is for information and education only and is not medical advice. For adults 18 and over. Read the full disclaimer.

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