Free Body Mass Index calculator gives out the BMI value and categorizes BMI based on provided information from WHO and CDC for both adults and children. Calculate your body mass index (BMI) Check an adult's or child's BMI to find out if they're a healthy weight. It's important to use the right calculator for adults (aged 18 and over) or children and teenagers (aged between 2 and 17). This calculator provides BMI and the corresponding BMI category for adults 20 and older. For children and teens 2 through 19 years, use the BMI Calculator for Children and Teens. Check your health with our free BMI Calculator. Instantly calculate your Body Mass Index for adults and children using official WHO and CDC guidelines. Calculate Your Body Mass Index. Body mass index (BMI) is a measure of body fat based on height and weight that applies to adult men and women. Calculate Your BMI Body mass index (BMI) is a measure of body fat based on height and weight that applies to adult men and… women. Your BMI is just one piece of the puzzle. It’s based on height and weight but doesn’t take into account your muscle mass, bone density, or body composition. Check your BMI to find out if you're a healthy weight for your height, and get advice on what to do next. This BMI calculator is for people over 18 years old. BMI is one potential health indicator and should be considered with other factors when assessing an individual's health. Persons may consider seeking advice from their health care providers about their BMI. This calculator is not a substitute for professional medical advice. Free online Body Mass Index Calculator (BMI Calculator) to determine your Body Mass Index & BMI category. Easily estimate your Body Mass Index based on weight and height (feet and inches, pounds, or meters and centimeters and kilograms). BMI calculator online: Get your Body Mass Index results fast. Check if you're underweight, normal, overweight, or obese. It's free!.