BMI Calculator

Calculate your Body Mass Index, see where it falls on the standard weight-status scale, and find the healthy weight range for your height.

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What BMI actually measures

Body Mass Index estimates body leanness or corpulence from just height and weight, and is widely used as a quick, general indicator of whether someone is underweight, normal weight, overweight, or obese. It's an imperfect measure — it can't distinguish muscle from fat — but it's a useful first signal for whether further testing might be worth it.

BMI Prime and Ponderal Index

BMI Prime is simply your BMI divided by 25 (the upper edge of the "normal" range), giving a dimensionless ratio that makes it easy to see how far above or below that threshold someone falls. The Ponderal Index is a similar leanness measure, but it cubes height instead of squaring it, which makes it more reliable than BMI for people at the very tall or very short ends of the height range.

BMI doesn't account for muscle mass, bone density, or body composition. A muscular athlete can show a high BMI while carrying very little body fat — BMI is best used as a starting point, not a diagnosis.

Common questions

Does this calculator account for children and teens?

You can enter any age, but the weight-status classification shown uses the standard adult (WHO) BMI ranges. Children and teens are typically assessed against age- and sex-specific percentile growth charts instead, which this calculator doesn't model.

Why does the healthy weight range change with height?

Because BMI itself is weight divided by height squared — for any given BMI target, taller people can weigh more and shorter people need to weigh less to land in the same range.

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