BMI Calculator
Medically reviewed by our Medical review board
cm
kg
About BMI Categories
UnderweightBMI: 0 - 18.5
NormalBMI: 18.5 - 24.9
OverweightBMI: 25 - 29.9
ObeseBMI: 30 - 100
Note: BMI is a general indicator and doesn't account for factors like muscle mass, age, gender, ethnicity, and body composition. Consult healthcare providers for personalized health assessments.
Overview
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)]²For 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) = 24.2BMI 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
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
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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
-
Enter Your Height:
Provide your height using the selected unit system. -
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.