Health tool
BMI Calculator
Enter your weight and height in metric or imperial units to see BMI, the adult category and the healthy weight range for your height.
The formula
Body Mass Index is weight in kilograms divided by height in metres squared: BMI = kg / m². In imperial units, the inputs are converted to metric first. The result is a single number that places you in a broad category.
Adult categories
| BMI | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 to 24.9 | Healthy weight |
| 25.0 to 29.9 | Overweight |
| 30.0 and above | Obesity |
These categories are for adults. They are not designed for children, pregnant people or athletes with a lot of muscle. A doctor may use additional measurements and context.
What BMI does not tell you
BMI does not distinguish muscle from fat, or show where fat is stored. Two people with the same BMI can have very different health risks. It is a screening measure, not a diagnosis. Use it as one data point, not a verdict.
Healthy weight range
The range shown is the weight that would produce a BMI between 18.5 and 24.9 for your height. It is a broad reference range, not a personal target. Age, body composition, medical history and other factors matter.
Units
Metric uses kilograms and centimetres. Imperial uses pounds, feet and inches. The conversion is done in the browser, and the result is shown in the units you selected.
Keep going
Related tools
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Good to know
Questions
Is BMI accurate for everyone?
No. It is a rough population-level screen. Athletes, older adults, pregnant people and children need different assessments. Talk to a healthcare professional for personal advice.
Why is my BMI different from another calculator?
Rounding and category boundaries can differ slightly. This tool uses the standard adult cut-offs and displays one decimal place.
Does it work for children?
No. Children and teenagers use age- and sex-specific BMI percentiles, not the adult categories shown here.
Is my data stored?
No. The calculation happens in your browser and is not sent to NelcByte.
What is a healthy BMI range for adults?
For most adults, 18.5 to 24.9 is described as a healthy range. BMI is a screening estimate and does not measure body fat, muscle or health directly.
Can I use this BMI calculator for children or pregnant people?
No. Child and teen BMI uses age- and sex-specific percentiles, and pregnancy changes the calculation. Ask a clinician for those cases.