Calculate your Body Mass Index from height and weight. Supports metric (cm/kg) and imperial (ft/in/lb) inputs.
Enter your height and weight in metric or imperial units to instantly calculate your BMI. The result shows your BMI value and the standard weight category (Underweight, Normal, Overweight, or Obese) on a color-coded scale. Note that BMI is a population-level screening tool and does not account for muscle mass, bone density, or body composition.
Choose Metric or Imperial using the toggle. Enter your height and weight — your BMI and weight category update immediately. The colored scale shows where your BMI falls relative to the standard ranges.
Body mass index remains common because it is simple, fast, and standardized. It gives one quick way to relate height and weight and place the result inside familiar categories. That simplicity is also the limitation. BMI is useful precisely when you treat it as a broad reference rather than a complete judgment about body composition or health.
This tool helps you get that reference quickly without manual unit conversion or formula work.
BMI remains a common reference in forms, check-ins, and broad population-level health discussions.
If someone wants a quick height-to-weight benchmark, BMI provides one of the most widely recognized versions.
If weight changes over time, BMI can show movement even when it cannot explain the reason behind that movement.
The main mistake is assuming the number explains more than it does.
BMI does not distinguish muscle from fat, does not capture body-fat distribution, and does not understand athletic build, age, or broader clinical context. That does not make it useless. It just defines the correct role for it: a screening figure, not a diagnosis.
Sometimes the reason to calculate BMI is simply that a familiar screening value is being requested.
A person who wants a quick orientation point can use BMI as a starting number before looking at anything deeper.
If the result changes over months rather than days, that can be a meaningful signal even if it is still incomplete.
The label can be standardized without being individually complete.
BMI becomes more useful over longer trends than over very short fluctuations.
Waist measurement, body composition, fitness, blood markers, symptoms, and clinical history can all matter more depending on the question.
This tool calculates BMI from height and weight. It does not measure body fat directly, assess muscularity, or replace professional medical judgment. It gives a common screening number and category, nothing more ambitious than that.
Even limited metrics can be useful when their limits are clear. BMI stays relevant because it is simple, standardized, and widely recognized. The important part is using it in the right scope.
The WHO defines a BMI of 18.5–24.9 as 'Normal weight'. Below 18.5 is Underweight, 25–29.9 is Overweight, and 30 or above is Obese.
Not always. BMI uses weight without distinguishing between fat and muscle. Athletes with high muscle mass often score as Overweight despite having low body fat. BMI is a screening tool, not a diagnostic one.
Yes. For people under 18, BMI is interpreted differently using age- and sex-specific percentile charts. This calculator uses adult BMI thresholds only.
This tool runs entirely in your browser. Nothing you type or paste is sent to any server — all processing happens locally on your device.