BMI is a reliable indicator of total body fat, which is related to the risk of disease and death. BMI does not measure body fat directly, but research

as shown that BMI correlates to direct measures of body fat and can be considered an alternative measures of body fat.  It is calculated by weight in kilograms divided by height in meters squared.
BMI is an easy-to-perform method of screening for weight categories that may lead to health problems.

The BMI equation does not take into account your body composition (percent muscle vs. fat) and is therefore less accurate if you have a non-typical amount of muscle. This is because while a person with an above average amount of muscle is likely to be healthier because of it, the equation simply interprets the added muscle as fat and overestimates obesity. The problem is compounded by the fact that muscle weighs more than fat.
Two people can have the same BMI, but a different percent body fat. A bodybuilder with a large muscle mass and a low percent body fat may have the same BMI as a person who has more body fat because BMI is calculated using weight and height only. These men have the same height, weight, and BMI, but may have different percent body fat.

6'3" Height 6'3" 220 lbs Weight 220 lbs 27.5 BMI 27.5

A more accurate assessment of weight can be made by measuring the percentage of body fat that makes up your body. Your doctor or local health club can likely do this, or you can purchase a home scale that has the capability to estimate body fat percentage.