# How To Calculate Your BMI—Body Mass Index

At some point in life, most people have received a BMI calculation. BMI stands for body mass index. It uses your height and weight to calculate general fitness. It’s a simple calculation that uses a chart with weight at the top and height at the side. It’s a quick way for physicians to identify whether you’re underweight, healthy, overweight, obese, or extremely obese. While men and women have separate charts, eliminating that issue, there are other problems if the BMI chart is the only way you calculate weight.

## The flaws in the height-to-weight BMI chart can make a difference.

The chart correlates your height-to-weight ratio with numbers ranging from 1-30. If you’re a 5’6″ female and weigh 150 pounds, you’d be healthy according to the BMI chart. If you gained five pounds, the chart says you’d be overweight. Suppose the extra five pounds came from muscle tissue weight. Muscle tissue weighs more per cubic inch than fat tissue does. You could potentially gain five pounds but be thinner. The BMI chart doesn’t allow for body build or the amount of muscle tissue you have. Insurance companies use BMI to evaluate health, too. Insurance companies have required bodybuilders with muscular physiques to send pictures or pay more for insurance because their BMI indicated they were obese.

## Calculate your ideal body weight.

BMI uses numbers to represent the height-to-weight ratio. Below 18.5 is underweight, 18.5 to 24.9 is healthy, 25.0 to 29.9 is overweight, and 30.0 and above is obese. You can calculate your number without using a chart. Take your weight in pounds divided by height in inches squared. Multiply that number by 703. BMI = weight in pounds / (height in inches X height in inches) X 703. If you’re a 5’7″ (67″) female who weighs 120 pounds, multiply your height in inches by your height in inches to get 4489. Then divide your weight by that number. 120/4489=0267320115838717. Multiply that number by 703 to get 18.7926. That falls into the healthy range.

## Bone structure plays a role.

People with larger bone structures can weigh more without looking overweight when compared to those with a smaller frame. If you have a higher BMI number, but a big build it can result in a false result. To find your body build, use your wrist measurements. Wrap the thumb and middle finger of one hand around the wrist of the other hand. If your finger and thumb don’t touch, your build is big. If they touch, your build is average. If you can overlap your finger and thumb, your build is small.

• Find your ideal body weight with a simple formula. Men start with 106 pounds for the first 60 inches and add 6 pounds for every inch more. Women use 100 pounds for the first 60 inches and add five pounds for each additional inch.
• Subtract 10% from the baseline ideal weight to find your ideal weight if you have a small frame. Add 10% to find the ideal weight for a large frame.
• Waistline circumference is a better predictor of health. Carrying your weight around your mid-section puts you at risk of health conditions. Men with a waist circumference of 40.2 inches or greater and women with a waistline of 34.6 inches or more face increased health risks.
• RFM, a new technique, stands for relative fat mass index. Waist measurement replaces weight as part of the calculation. It’s just as easy as BMI but more accurate at predicting health.