BMI Calculator Uses and Work

Written by - Reviewed by Consumer Health Digest Team

Published: Jul 29, 2013 | Last Updated: Feb 7, 2019

BMI Calculator

BMI Overview

The Body Mass Index (BMI) is a measure of body fat by comparing your body weight to your height. This ratio determines whether you are at a healthy weight, underweight or overweight. In countries that use the metric system, BMI can be calculated in meters and kilograms. In the United States, it is calculated in inches and pounds.

Gauging the severity of excess weight

BMI of 25 to 29.9 – overweight
This indicates that the person has too much body weight for his height.

BMI of 30 or higher – obese
This indicates that the person has a large amount of body fat as compared to his height.

Since it is an estimate of body fat, BMI can also measure the risks of health problems that may occur with overweight and obesity. The higher the BMI, the higher the risk for diseases, such as high blood pressure, heart disease, type 2 diabetes, osteoarthritis, gallstones, sleep apnea and certain cancers.

Why Use BMI Calculator?

Knowing that the calculation only requires height and weight, BMI is an easy-to-perform and inexpensive screening tool to identify probable weight problems for adults. The Centers for Disease Control (CDC) also uses this calculation for population assessment of overweight and obesity.

Many companies use BMI as a requirement as criteria for job hires even eligibility for weight loss surgeries, like gastric bypass surgery and Bariatric surgery.

How It Works?

Do you want to lose weight? Or gain weight? BMI is a good indicator to know if you are on the right track. You can find some health sites that offer free BMI calculator. In fact, you can even install a BMI calculator app on your mobile. But if you want to know how you calculate it by hand, the formula looks like this.

In Inches:


A person who weighs 190 pounds and is 5 feet 8 inches tall has a BMI of 28.9.


In Meters:


A person who weighs 52 kilograms and is 1.6905 meters tall has a BMI of 27.5.


Take note, however, that BMI has its limitations. It may overestimate the body fat in athletes and other people with a muscular built; and underestimate body fat in older people who have lost muscle mass with age.

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