Calculators
BMI Calculator
Calculate BMI from height in centimetres and weight in kilograms, or switch to feet, inches and pounds. Includes WHO adult category and healthy weight range.
Body measurements
Results
BMI
23.5
Category
Normal weight
Healthy weight range
53.5 – 72 kg
WHO adult categories (ages 20+): under 18.5 underweight, 18.5–24.9 normal weight, 25–29.9 overweight, 30+ obesity. BMI is a population screening tool, not a clinical diagnosis. Not intended for children or teens.
About this tool
BMI is weight relative to height. Enter height in cm and weight in kg (or switch to feet, inches and pounds). You get a BMI score, a WHO adult category and the healthy weight band for that height. It is a screen, not a diagnosis.
How to use
- Leave units on Metric (cm, kg), or switch to Imperial (ft, in, lb).
- Enter height and weight.
- Read BMI, WHO adult category and the healthy weight range.
How to Calculate BMI Using KG and CM
1. Convert height in centimetres to metres: divide by 100. 2. Square that height in metres. 3. Divide weight in kilograms by the squared height. BMI = kg ÷ m². Imperial entries are converted first (1 inch = 0.0254 m, 1 lb = 0.45359237 kg) or use BMI = (lb ÷ in²) × 703. WHO adult bands: under 18.5 underweight, 18.5–24.9 normal, 25.0–29.9 overweight, 30.0+ obesity.
Worked example
Height 170 cm → 1.70 m. 1.70 × 1.70 = 2.89. Weight 68 kg. BMI = 68 ÷ 2.89 ≈ 23.5 (normal). Healthy weight for 170 cm is about 53.5–72.0 kg — the weights that produce BMI 18.5–24.9.
Frequently asked questions
How do I calculate BMI using cm and kg?+
Convert height in cm to metres by dividing by 100 (e.g., 170 cm = 1.70 m). Square that number (1.70 × 1.70 = 2.89). Then divide your weight in kg by the squared height (68 ÷ 2.89 = 23.5).
What are the limitations of BMI?+
BMI screens weight relative to height but does not measure body fat percentage, muscle mass, bone density, or fat distribution. For athletes or muscular individuals, BMI may overestimate body fat; for older adults with muscle loss, it may underestimate it.
Can this calculator be used for children or teenagers?+
No. This calculator is designed for adults aged 20 and older. Pediatric BMI interpretation requires age- and sex-specific growth percentiles (CDC/WHO growth charts), as body composition changes rapidly during childhood and adolescence.
What is considered a healthy BMI range?+
For adults, the World Health Organization defines a BMI between 18.5 and 24.9 as the normal or healthy weight range.
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