Tool
BMI Calculator
See where a body mass index falls on the standard adult scale, with a gauge, the weight range for your height at each category, and the weight at any BMI you choose. Arithmetic only.
BMI is a screening number. It does not measure body fat or health, it can misread very muscular people and some older adults, and it is for adults 18 and over. This tool does not give medical advice. Talk to a licensed healthcare professional about your health.
Your result
Choose your height and weight and your result builds here.
- Body mass index
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- Category
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- Healthy range for your height
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The bar shows your weight against the BMI categories for your height.
Download your reference sheet
A letter-size PDF with your BMI result, the gauge and the weight bands for your height.
Your browser opens its print window. Choose Save as PDF as the destination.
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Adult BMI categories
| Underweight | Below 18.5 |
|---|---|
| Healthy weight | 18.5 to 24.9 |
| Overweight | 25.0 to 29.9 |
| Obesity class 1 | 30.0 to 34.9 |
| Obesity class 2 | 35.0 to 39.9 |
| Obesity class 3 | 40.0 and above |
How BMI is calculated
- BMI = weight (kg) ÷ height (m) squared
- In pounds and inches: BMI = 703 × weight (lb) ÷ height (in) squared
- Weight at a chosen BMI = BMI × height (m) squared
Worked example, for illustration only: 70 kg at 1.75 m is 70 ÷ (1.75 × 1.75) = 22.9.
BMI questions
What is BMI?
Body mass index compares weight with height. It is one number used to screen groups of adults. It is not a diagnosis.
What are the limits of BMI?
BMI does not separate muscle from fat or show where fat sits. It can read high in very muscular people and low in some older adults, and the cutoffs can differ for some populations. Waist size, blood tests and an assessment by a clinician give a fuller picture.
Does it work for children or teenagers?
No. For people under 18, BMI is read against age and sex percentiles. Ask a pediatrician.
Does the calculator tell me what weight to aim for?
No. It converts numbers. The healthy range is the weight band the adult BMI scale labels 18.5 to 24.9 at your height, and the target row is arithmetic for a BMI you pick. Goals belong with a licensed healthcare professional.
Is this reference for human use?
This site is for educational and entertainment purposes only. Nothing here is medical advice, and nothing here recommends use in people.
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