BMI is a quick screening number, not a verdict. The category below is a starting point for a closer look, not the final word on your health.
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BMI Calculator
Body Mass Index, the healthy-weight range for your height, and where that falls on the scale, with weight and height each in whichever unit you actually use.
Illustrative only, a simplified visual reference, not a depiction of your actual body or anyone else's.
This is general educational information based on population-level research, not a medical diagnosis or personalized advice. BMI has real limits (see below) and doesn't account for muscle mass, fat distribution, age or individual health. Always consult a qualified healthcare provider for guidance specific to you.
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What BMI does and doesn't tell you
BMI is a screening number, not a diagnosis. It compares your weight to your height using a simple formula that was designed for population-level statistics, not for judging any one person's health from a single number. It doesn't distinguish muscle from fat, so a muscular athlete can show as "overweight" while carrying very little body fat, and it isn't calibrated for children, pregnant women, or adults over 65, whose healthy ranges differ from the standard adult chart used above. If BMI puts you outside the "normal" range, that's a reason to look closer, with a doctor, a body fat measurement, or both, not a verdict on its own.
Why the figure doesn't change shape much, and why there's a gauge next to it
The illustration above is deliberately restrained, a simplified reference point, not an attempt to show what any real body at a given BMI actually looks like, since real bodies at the same BMI vary enormously in build, muscle, and fat distribution. The numbers do the actual work: the gauge marks exactly where your BMI falls on the underweight-to-obese scale, which is the part worth reading closely, the figure next to it is only a gentle visual echo of that same number, not a claim about how you or anyone else looks.
BMI calculator FAQ
What is a healthy BMI range?
18.5 to 24.9 is classified as normal weight for most adults, under 18.5 is underweight, 25 to 29.9 is overweight, and 30 or above is obese, split into three classes. These are the standard WHO and CDC adult cutoffs used above.
How is BMI calculated?
BMI = weight in kilograms divided by height in meters squared. In imperial units, BMI = 703 x weight in pounds divided by height in inches squared. Both formulas give the same result, just expressed in different units.
Is BMI accurate for athletes and muscular people?
Not really. BMI cannot distinguish muscle from fat, so a muscular, lean athlete often scores as "overweight" or even "obese" despite having low body fat. If that sounds like you, a body fat percentage measurement is a far more meaningful number than BMI.
Does BMI apply to children?
No, not the adult cutoffs used here. Children and teens are assessed with age- and sex-specific BMI-for-age percentile charts instead, since healthy body composition changes a lot through growth. This calculator is for adults.
Is my data private?
Yes. Every calculation runs in your browser. Nothing you enter is sent to a server, logged, or stored.
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What a “normal” BMI actually covers
The 18.5 to 24.9 band that counts as normal weight is wide on purpose, it was built from population health statistics, not from any one body type. Two people can share the same BMI and look completely different in muscle mass, frame size and where they carry weight, which is exactly why doctors treat BMI as a first-pass screen rather than a diagnosis on its own.
Where BMI genuinely gets it wrong
Muscle weighs more than fat by volume, so a lean, muscular person routinely scores as “overweight” on BMI alone despite having low body fat, and the same limitation runs the other way for someone with low muscle mass and higher fat percentage sitting in the “normal” range. If your BMI result surprises you, our Body Fat Calculator gives a very different, often more useful, picture of the same body.
The number behind the number
Every BMI result on this page also comes with the actual weight range, in your own units, that would put you in the healthy band at your current height. That’s usually more actionable than the BMI figure itself: a target range in kilograms or pounds is something you can plan around, a unitless index number is harder to act on directly.