BMI Calculator — Body Mass Index Calculator
Calculate your Body Mass Index instantly. Enter your height and weight to find out if you're underweight, normal, overweight or obese.
By SwiftCalcTools Editorial Team · Formula verified
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How to Use BMI Calculator
- 1Enter the required values in the input fields above.
- 2Click the Calculate button or results update instantly as you type.
- 3View your results in the output panel below the inputs.
- 4Adjust any values to recalculate instantly.
Formula & Method
BMI = weight (kg) ÷ height² (m²)
Frequently Asked Questions
A BMI between 18.5 and 24.9 is considered normal or healthy for most adults. Below 18.5 is underweight, 25–29.9 is overweight, and 30 or above is classified as obese.
BMI does not distinguish between muscle and fat mass. Athletes and very muscular individuals may have a high BMI despite having low body fat. For a more accurate assessment, body composition measurements are recommended.
Yes. For children and teens (ages 2–19), BMI is interpreted using age- and sex-specific percentile charts rather than fixed cut-off numbers.
To find your ideal weight, rearrange the formula: Ideal weight = 18.5 to 24.9 × height (m)². For a 175 cm person, the healthy weight range is approximately 56.5–76.5 kg.
For most adults, checking BMI once or twice a year is sufficient. More frequent checks can be useful if you are on a weight-loss or muscle-building programme.
Clinicians use BMI as a quick population-level screening tool to identify individuals who may be at risk for weight-related health conditions such as type 2 diabetes, hypertension, and cardiovascular disease. It is not a diagnostic tool on its own.