calctool.app

BMI Calculator

Calculate your Body Mass Index from height and weight in imperial or metric units, with category ranges.

Your BMI
24.3
Normal weight

Frequently Asked Questions

How is BMI calculated?+

BMI is weight divided by height squared. In metric units: BMI = kg ÷ m². In imperial units: BMI = 703 × lb ÷ in². The 703 factor converts pounds and inches to the metric scale so both methods give the same number.

What are the BMI categories?+

The standard adult ranges are: under 18.5 is underweight, 18.5–24.9 is normal weight, 25–29.9 is overweight, and 30 or above is obese. These are general screening bands, not a diagnosis.

Why is BMI sometimes misleading?+

BMI only uses height and weight, so it cannot distinguish muscle from fat or account for frame size, age, or sex. Athletes with high muscle mass can score as "overweight", while a "normal" BMI can still hide excess body fat. Pair it with other measures like waist circumference or a body fat estimate.

Is my data kept private?+

Yes. The calculation runs entirely in your browser. Your height and weight are never sent to a server or stored.

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How to use

  • Pick Imperial (ft + in, lb) or Metric (cm, kg) units.
  • Enter your height and weight — in imperial, enter feet and inches separately.
  • Your BMI and its category appear instantly.