Calcwise / Health / BMI calculator
BMI calculator
Enter your weight and height to see your body mass index.
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About this tool: BMI calculator
Body mass index (BMI) compares your weight with your height. The World Health Organization uses it to group adults as underweight (below 18.5), healthy (18.5 to 24.9), overweight (25 to 29.9) or obese (30 and above).
BMI is a quick screening number, not a diagnosis. It does not tell muscle from fat, so athletes can score high, and it does not suit children, pregnant women or older people in the same way. Talk to a doctor about your health.
Formula
BMI = weight in kg ÷ (height in metres)². With pounds and inches: BMI = 703 × weight in lb ÷ (height in inches)².
Worked example
70 kg and 175 cm: BMI = 70 ÷ (1.75 × 1.75) = 22.9, which is healthy weight. For that height the healthy range is about 56.7 to 76.3 kg.
Sources and data
- Formulas and data last reviewed
- Accuracy
- The result is a rough guide and does not replace advice from a doctor or dietitian.
Sources and data
Frequently asked questions
What is a healthy BMI?
For adults, a BMI from 18.5 to 24.9 is classed as a healthy weight by the World Health Organization.
Is BMI accurate for athletes?
Not always. Muscle weighs more than fat, so a muscular person can have a high BMI while being lean.
Is this medical advice?
No. BMI is a rough guide only. For advice about your weight and health, see a doctor or a dietitian.