What's the BMI formula?

BMI = weight (kg) ÷ height² (m). E.g. 70 kg and 1.75 m: 70 ÷ (1.75 × 1.75) = 22.9.

What's the ideal BMI?

The WHO considers 18.5–25 as normal weight for adults. Below: underweight; above: overweight then obese.

Is BMI reliable for everyone?

No. It's not suitable for children, pregnant women, the elderly, or highly muscular athletes. It's a statistical indicator, not a diagnosis.

What if my BMI is outside the normal range?

BMI alone isn't enough. Consult a doctor or dietitian for an overall assessment factoring in lifestyle, body shape and health.

Health

BMI calculator

Calculate your Body Mass Index from your height and weight. Interpretation based on the World Health Organization classification.

Height (cm)

Weight (kg)

Your BMI

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How to use this tool

BMI (Body Mass Index) is a simple indicator of the weight-to-height ratio, used by the WHO to place an adult in a body size category. It is calculated by dividing weight (in kilograms) by the square of height (in meters). Note: it's a general indicator and doesn't account for muscle mass, body shape, or fat distribution. Muscular athletes often show a 'high' BMI without being overweight.

Concrete examples

5'7" at 143 lb → BMI 22.5 (normal)
5'11" at 209 lb → BMI 29.3 (overweight)
5'5" at 115 lb → BMI 19.1 (normal)

Frequently asked questions

What's the BMI formula?: BMI = weight (kg) ÷ height² (m). E.g. 70 kg and 1.75 m: 70 ÷ (1.75 × 1.75) = 22.9.
What's the ideal BMI?: The WHO considers 18.5–25 as normal weight for adults. Below: underweight; above: overweight then obese.
Is BMI reliable for everyone?: No. It's not suitable for children, pregnant women, the elderly, or highly muscular athletes. It's a statistical indicator, not a diagnosis.
What if my BMI is outside the normal range?: BMI alone isn't enough. Consult a doctor or dietitian for an overall assessment factoring in lifestyle, body shape and health.

This tool is provided for informational purposes and does not replace the advice of a healthcare professional.