How to use BMI calculator
- Choose Metric or US units.
- Enter height and weight.
- Read your BMI, category and healthy range.
Questions
How is BMI calculated?
Weight in kilograms divided by height in meters squared. 68 kg at 1.70 m is 68 ÷ (1.70 × 1.70) = 23.5.
What are the BMI categories?
For adults: under 18.5 underweight, 18.5–24.9 healthy weight, 25–29.9 overweight, 30 and above obesity.
Is BMI accurate for everyone?
No. It doesn't distinguish muscle from fat and isn't designed for children, pregnancy or some ethnic groups. Use it as a rough guide and talk to a doctor.
Last updated 13 November 2026.