BMI, or body mass index, is a calculation that allows doctors to rapidly screen people for weight problems. The formula takes into account only your height and weight, so it is not a perfect measure. However, it can quickly screen people, making its use widespread. According to the Center for Disease Control, the BMI formula is the same for both men and women. However, men tend to have lower body fat levels than women who have the same BMI.
Multiply your weight in pounds by 703. For example, if you weigh 180 pounds, you would multiply 180 by 703 to get 126,540.
Multiply your height in inches by itself. For example, if you are 71 inches tall, you would multiply 71 by 71 to get 5,041.
Divide the result from Step 1 by the result from Step 2 to calculate your BMI. Finishing the example, you would divide 126,540 by 5,041 to get a BMI of 25.1