Health
How do you calculate BMI from weight and height?
Calculate your BMI from weight and height with the WHO classification.
Quick answer
BMI (body mass index) = weight in kg ÷ height in metres squared. At 70 kg and 175 cm (1.75 m): 70 ÷ (1.75 × 1.75) = 70 ÷ 3.06 = 22.9 — within the WHO normal range (18.5–24.9).
BMI
22.9
- WHO classification
- Normal weight
- Normal weight range for your height
- 56.7 – 76.3 kg
BMI is a statistical indicator and does not account for muscle mass, age or body type. It does not replace advice from a doctor or dietitian.
How it works
BMI is a quick screening tool used by doctors and insurers worldwide. It does not distinguish muscle from fat: a lean athlete and a sedentary person at the same BMI can have very different body composition. Use it as one data point, not a diagnosis.
Frequently asked questions
What BMI is considered overweight?+
WHO classification: under 18.5 underweight, 18.5–24.9 normal, 25–29.9 overweight, 30+ obesity (three classes above 30). Asian populations sometimes use lower cut-offs (overweight from 23) due to different fat-distribution risk.
Is BMI accurate for muscular people?+
No — muscle is denser than fat, so athletes often score "overweight" on BMI despite low body fat. Waist circumference, body-fat percentage or DEXA scans give a clearer picture for muscular individuals.
What is a healthy weight for my height?+
Multiply your height in metres squared by 18.5 and 24.9. At 1.75 m: 56.7–76.3 kg. The calculator above shows this range automatically alongside your BMI classification.
Should children use the same BMI ranges?+
No. Paediatric BMI uses age- and sex-specific percentiles, not fixed adult cut-offs. A BMI of 20 means something different at age 8 vs age 15. This calculator is for adults (18+).
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