BMI Calculator
Calculate your Body Mass Index (BMI), view official WHO weight classifications, and find your healthy target weight range.
kg / m²
World Health Organization category
For a normal 18.5 – 24.9 BMI
(< 18.5)
(18.5 – 24.9)
(25 – 29.9)
(≥ 30.0)
How Body Mass Index (BMI) Is Calculated
Originally developed in the 19th century by Belgian polymath Adolphe Quetelet, the Quetelet Index (now Body Mass Index) remains the global standard epidemiological screening tool used by healthcare organizations worldwide.
BMI Mathematical Formulas
Clinical & Personal Uses
- ✓General Health & Wellness Screening
Check whether your body weight falls within the epidemiologically normal risk category for cardiovascular disease and diabetes.
- ✓Setting Realistic Weight Loss Goals
Determine the upper threshold of your recommended healthy weight range to set actionable target weights.
- ✓Life Insurance & Medical Underwriting
Anticipate health underwriting tier classifications used by term life and disability insurance providers.
- ✓Youth & Adult Fitness Benchmarking
Track baseline physique changes during lifestyle, nutrition, and exercise interventions.
Why Use This BMI Calculator
Metric & Imperial Unit Switching
Seamlessly toggle between standard US units (feet, inches, pounds) and international metric units (centimeters, kilograms).
Official WHO Weight Categories
Classifies scores into Underweight (<18.5), Normal (18.5–24.9), Overweight (25–29.9), and Obese (30+).
Ideal Healthy Weight Range
Computes the exact minimum and maximum healthy weight targets tailored to your specific height.
Visual Color-Coded Gauge Bar
Interactive marker visually positions your score along the spectrum of adult BMI classifications.
Frequently Asked Questions
What is Body Mass Index (BMI)?
Body Mass Index (BMI) is a widely used screening metric that evaluates body weight in relation to height: BMI = weight (kg) / [height (m)]^2. It provides a simple, non-invasive benchmark to categorize whether an individual is underweight, normal weight, overweight, or obese.
What are the official WHO BMI categories?
According to the World Health Organization (WHO): Underweight is a BMI below 18.5; Normal (Healthy) Weight is 18.5 to 24.9; Overweight is 25.0 to 29.9; and Obese is 30.0 or higher.
What are the limitations of BMI?
BMI does not directly measure body fat percentage or distinguish between fat and muscle mass. As a result, muscular athletes and bodybuilders may register as 'overweight' or 'obese' despite having low body fat, while older adults with sarcopenia may register as 'normal' despite high visceral fat.
What is a healthy BMI for men and women?
For both adult men and adult women, a BMI between 18.5 and 24.9 is considered the healthy normal range associated with the lowest risk of chronic illness and all-cause mortality.
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