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BMI Formula:
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Body Mass Index (BMI) is a simple calculation using a person's height and weight. The formula is BMI = kg/m² where kg is a person's weight in kilograms and m² is their height in meters squared. BMI provides a reliable indicator of body fatness for most people and is used to screen for weight categories that may lead to health problems.
The calculator uses the standard BMI formula:
Where:
Explanation: The formula divides your weight in kilograms by the square of your height in meters. This gives a number that corresponds to standard weight categories.
Details: BMI is a simple, inexpensive screening method for weight category—underweight, healthy weight, overweight, and obesity. While BMI doesn't measure body fat directly, research has shown that BMI is moderately correlated with more direct measures of body fat.
Tips: Enter your weight in kilograms and height in meters. For most accurate results, measure your height without shoes and weight with minimal clothing. All values must be valid (weight > 0, height > 0).
Q1: What are the standard BMI categories?
A: Underweight (BMI < 18.5), Normal weight (18.5-24.9), Overweight (25-29.9), and Obese (≥30).
Q2: Is BMI accurate for everyone?
A: BMI may overestimate body fat in athletes and others with muscular builds, and may underestimate body fat in older persons and others who have lost muscle.
Q3: What are the health risks associated with high BMI?
A: Higher BMI is associated with increased risk of heart disease, high blood pressure, type 2 diabetes, gallstones, breathing problems, and certain cancers.
Q4: What if I know my height in feet/inches and weight in pounds?
A: Convert height to meters (1 foot = 0.3048m, 1 inch = 0.0254m) and weight to kilograms (1 pound = 0.453592kg) before using this calculator.
Q5: Should children use the same BMI categories?
A: No, children and teens need BMI-for-age percentiles that consider age and sex differences in body fat.