The normal BMI for a person is between 18.5 – 24.9. Within this range you are considered to be at the correct weight for your height. Individuals who have a BMI between 25 -29.9 are classed as being overweight, those with a BMI over 30 are considered obese. Generally speaking the higher the BMI the more overweight a person is.
BMI is a good indicator of obesity in most individuals however it may not be suitable for everyone. In people with a highly muscular physiques (e.g. bodybuilders), the BMI may be very high, however they cannot be classed as obese as their body fat is low. This is as muscle weighs more than fat and contributes to the high BMI value.