BMI Calculator (Body Mass Index)

Calculate Body Mass Index (BMI), ideal weight range, and WHO health categories.

Tool Guide

BMI Calculator (Body Mass Index): What It Does

Calculates Body Mass Index (BMI) from metric or imperial height and weight. It provides standard WHO category classifications (underweight, normal, overweight, obesity) and ideal weight ranges.

Example

Input
Weight: 70 kg, Height: 175 cm
Output
BMI: 22.86 (Normal weight)

Divides weight in kilograms by height in meters squared (70 / 1.75^2).

How to Use

  1. Select metric (cm/kg) or imperial (feet/inches/lbs) measurement units.
  2. Enter height and weight into the inputs.
  3. Review the BMI score, weight category indicator, and healthy target range.

Limitations

  • BMI does not distinguish between muscle mass, bone density, and body fat percentage.
  • Standard categories may vary for athletes, pregnant women, and older adults.

Frequently Asked Questions

What are the standard WHO BMI categories?

Under 18.5 is underweight, 18.5 to 24.9 is normal weight, 25 to 29.9 is overweight, and 30 or higher indicates obesity.

Why is BMI considered a screening tool rather than a diagnostic measure?

BMI correlates with body fat on a population level, but cannot differentiate lean athletic muscle mass from adiposity in individuals.

Inputs stay in browser memory. No external request is required for this operation, and zero data leaves your device.