BMI Calculator

Estimate your Body Mass Index in metric or imperial units and see which standard category it falls in.

Height (cm)

Weight (kg)

BMI: –

This is an educational estimate for adults and is not medical advice. BMI does not distinguish muscle from fat. Consult a healthcare professional about your health.

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How it works

Body Mass Index is a simple screening number that relates your weight to your height. In metric units the formula is weight in kilograms divided by height in metres squared; in imperial units it's 703 times weight in pounds divided by height in inches squared. Both give the same BMI value.

The widely used adult categories are: underweight below 18.5, normal weight from 18.5 to 24.9, overweight from 25 to 29.9, and obese at 30 and above. This tool shows your value and highlights the matching category with a colored badge.

BMI is a population-level screening tool, not a diagnosis. Because it uses only height and weight, it can't tell muscle from fat — very muscular people may read as "overweight" despite low body fat, and it isn't validated for children, pregnancy, or the elderly in the same way. Treat the number as one rough data point and speak with a healthcare professional about your individual health.

Examples

175 cm, 70 kg → BMI 22.9 → Normal weight

5 ft 9 in, 154 lb → BMI 22.7 → Normal weight

160 cm, 80 kg → BMI 31.3 → Obese (screening category)

Frequently asked questions

What BMI is considered healthy?

For most adults, a BMI between 18.5 and 24.9 is labelled 'normal weight'. This is a general screening range, not a personal health verdict.

Is BMI accurate for athletes?

Not reliably. BMI counts muscle and fat the same way, so muscular people can score as 'overweight' despite being lean. Body-composition measures are better for athletes.

Does this work for children?

No. Children and teens use age- and sex-specific BMI percentiles, which this adult calculator doesn't apply. Consult a paediatric chart or professional.

Is any of my data saved?

No. Your height and weight are used only to compute BMI in your browser and are never stored or sent anywhere.