BMI Calculator
Calculate Body Mass Index in metric or imperial units with category ranges.
Calculators
HEIGHT/WEIGHT → BMI
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Body Mass Index is a quick screening number that relates your weight to your height. It does not measure body fat directly, but it is a widely used starting point for thinking about a healthy weight range. This calculator works in both metric and imperial units and shows which category your result falls into.
How to calculate your BMI
- Choose metric (cm / kg) or imperial (ft-in / lb).
- Enter your height and weight.
- Read your BMI and its category.
- Use it as one input among many when discussing health with a professional.
Standard adult BMI categories
| BMI range | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Healthy weight |
| 25.0 – 29.9 | Overweight |
| 30.0 and above | Obesity |
BMI is a general guide for adults and does not account for muscle mass, age or body composition. It is not medical advice.
Calculator features
- Metric and imperial units.
- Instant BMI value with its category.
- Clear ranges so you can see where you sit.
- Calculated locally — your measurements stay private.
Frequently asked questions
Is BMI accurate for athletes?
Not always. Muscle weighs more than fat, so very muscular people can register as “overweight” despite low body fat. Treat BMI as a rough screen.
How is BMI calculated?
Metric: weight (kg) ÷ height (m) squared. The imperial formula multiplies by a conversion factor; this tool handles it for you.
Does BMI work for children?
Children use age- and sex-specific percentiles instead of the adult categories shown here. Consult a paediatric chart.