BMI Calculator

What is BMI?

BMI, or Body Mass Index, is a simple numerical measure that estimates body fat based on height and weight. It’s used to categorize individuals into weight categories that may indicate potential health risks.

The formula for BMI is:

BMI = weight (kg) / [height (m)]²

For example, someone who weighs 70 kg and is 170 cm (1.7 m) tall would have a BMI of:

BMI = 70 / (1.7 × 1.7) = 24.2

BMI Categories

Category	BMI Range
Underweight	Less than 18.5
Normal	18.5 – 24.9
Overweight	25 – 29.9
Obese	30 or higher

Limitations of BMI

• BMI does not distinguish between muscle and fat mass.
• It may overestimate body fat in athletes or muscular individuals.
• It may underestimate fat in older adults or people with low muscle mass.
• Does not account for sex, ethnicity, or body composition.

Why It’s Still Useful

Despite its limitations, BMI is a useful population-level screening tool. It’s easy to calculate, widely understood, and often used by healthcare professionals to flag potential health issues related to weight.

How to Use the BMI Calculator

This calculator helps estimate your Body Mass Index (BMI), which is a simple numerical value of your weight in relation to your height. It's widely used to assess whether you're underweight, normal weight, overweight, or obese.

Steps to Use

1. Select the Unit System:
   Choose between:
   • Metric (cm, kg): Centimeters for height and kilograms for weight
   • Imperial (ft/in, lb): Feet/inches for height and pounds for weight
2. Enter Your Height:
   Provide your height using the selected unit system.
3. Enter Your Weight:
   Input your body weight in the matching unit.

View Your Results

Once both height and weight are entered, the calculator instantly shows your BMI value along with the category you fall into — such as Normal, Overweight, or Obese — highlighted for clarity.

Note:

BMI is a screening tool and doesn't account for muscle mass, age, sex, or ethnicity. Athletes and muscular individuals may appear "overweight" due to lean body mass. Always consult a healthcare provider for a more accurate health assessment.