BMI calculator
Body mass index from weight and height, with the standard adult category.
Enter your values and press Calculate. Your inputs stay in the address, so you can switch language or share the link.
Formula
BMI = weight (kg) ÷ height (m)²
How it works
BMI compares weight with height squared. The categories are the World Health Organization adult ranges.
Worked example
The same calculation with the default values:
- Weight 70 kg
- Height 175 cm
- height = 175 cm ÷ 100 = 1.75 m
- BMI = 70 ÷ 1.75² = 22.857143
Result: BMI: 22.85714286 kg/m² · Adult category: Healthy weight range (18.5 to 24.9)
BMI is a screening figure, not a diagnosis. It does not suit children, pregnancy, athletes or older adults in the same way. Speak to a health professional about your health.
Common mistakes
- Applying adult BMI categories to a child or teenager - children need age- and sex-adjusted percentile charts, not the fixed adult cutoffs used here.
- Treating a high BMI in a muscular, athletic person as a sign of excess body fat - BMI cannot tell muscle mass from fat mass.
- Using a single BMI reading as a complete health assessment instead of one screening number among several (waist measurement, body composition, blood tests, a clinician's judgment).
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