Health
BMI Calculator
Calculate your Body Mass Index (BMI) and determine your weight category based on standard clinical thresholds.
Inputs
Results
Body Mass Index (BMI)
0.0
Weight Category
Normal Weight
Healthy Weight Range
0 - 0 kg
How It Works
Body Mass Index (BMI) is a simple numerical measurement of weight relative to height, widely used as an initial screening tool for body weight classifications.\n\nThe calculation divides weight in kilograms by the square of height in meters ($BMI = kg/m^2$). In imperial units, the index is calculated as: $703 \times (lbs/inches^2)$. Weight status categories are defined by the World Health Organization (WHO).
Formula Used
BMI = Weight (kg) / Height (m)^2
Body Mass Index (BMI) is a standardized metric that measures body mass relative to height. Squaring the height accounts for the three-dimensional scaling of weight relative to two-dimensional stature.
BMI (Imperial) = 703 × Weight (lbs) / Height (inches)^2
This is the imperial version of the BMI equation. The scaling factor of 703 converts pounds per square inch into the metric equivalent of kilograms per square meter.
Worked Example
Here is a step-by-step example of how these values are calculated:
Weight
70 kg
Height
175 cm
Result: BMI: 22.9. Weight Category: Normal Weight. Healthy weight range for this height: 56.7 to 76.3 kg.
Frequently Asked Questions
Is BMI a reliable indicator of health?
BMI is a general screening indicator. It does not measure body fat directly and cannot differentiate between fat and muscle tissue. Athletes with high muscle mass may index as 'overweight' despite having low body fat.
What are the standard weight category thresholds?
Standard WHO classifications define: Underweight (< 18.5), Normal Weight (18.5 - 24.9), Overweight (25 - 29.9), and Obese (>= 30).