BMI Calculator
Check your Body Mass Index and weight category
kg
cm
What is BMI?
Body Mass Index (BMI) is a simple screening measure that estimates whether your weight is in a healthy range relative to your height. It's calculated the same way for adults regardless of country and is widely used by doctors as a quick first indicator — though it doesn't distinguish between muscle and fat mass.
How to Use the BMI Calculator
- Choose metric or imperial units.
- Enter your weight and height.
- Read your BMI and category — updated instantly as you type.
BMI Formula
Metric: BMI = weight (kg) ÷ height (m)²
Imperial: BMI = 703 × weight (lb) ÷ height (in)²
Imperial: BMI = 703 × weight (lb) ÷ height (in)²
BMI Categories
| BMI Range | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Normal weight |
| 25.0 – 29.9 | Overweight |
| 30.0 and above | Obese |
BMI is a general screening tool, not a diagnosis. It doesn't account for muscle mass, bone density, age or sex, so athletes and older adults in particular may fall outside "normal" while still being healthy. Talk to a doctor for a full health assessment.
Frequently Asked Questions
Not perfectly — BMI doesn't distinguish muscle from fat, so very muscular people can show a high BMI despite low body fat. It's best used as a general starting point alongside other measures like the Body Fat Calculator.
For most adults, 18.5–24.9 is considered a normal, healthy range. This threshold is used consistently across the US, UK, Canada and Australia.
No — this calculator is designed for adults. Children and teens need age- and sex-specific BMI percentile charts, which a pediatrician can provide.
Advertisement
Responsive