BMI Calculator
Evaluate your body mass relative to height using the official World Health Organization (WHO) Body Mass Index standards. Enter your weight and height to view your BMI score, clinical classification, Ponderal Index, and target healthy weight envelope in real time.
Current body weight measured in kilograms
Standing barefoot height in centimetres
Body weight in kg divided by square of height in meters
How to Use This Calculator
- Measure your body weight in the morning barefoot using a calibrated digital scale.
- Measure your stature against a flat vertical wall with heels touching the skirting.
- Enter your weight in kilograms and height in centimetres into the fields above.
- Review your immediate BMI score, WHO classification, and healthy weight goal.
Formula & Calculation Methodology
Body Mass Index is computed by taking an individual weight in kilograms and dividing it by the square of their height in metres. BMI Prime normalizes the value against 25 kg/m², where scores below 1.0 denote underweight or normal ranges.
Worked Example
An adult weighing 70 kg with a height of 175 cm (1.75 m)
Frequently Asked Questions
What are the official World Health Organization BMI categories?↓
The WHO defines adult BMI cut-offs as follows: Underweight (< 18.5), Normal weight (18.5–24.9), Overweight (25.0–29.9), Obesity Class I (30.0–34.9), Obesity Class II (35.0–39.9), and Obesity Class III (≥ 40.0).
Does BMI distinguish between muscle mass and body fat?↓
No. BMI is a general population screening metric. Because dense muscle tissue weighs more than fat volume, athletes, bodybuilders, and heavy laborers may register as overweight or obese despite possessing low body fat percentages.
Why do Asian populations sometimes use adjusted BMI thresholds?↓
Clinical studies by the WHO Western Pacific Region demonstrate that individuals of South and East Asian descent face higher risks of cardiovascular disease and type 2 diabetes at lower BMI levels, prompting recommended cut-offs of 23.0 for overweight and 27.5 for obesity.
What is BMI Prime and how should I interpret it?↓
BMI Prime is the ratio of your calculated BMI to 25.0 (the upper limit of normal weight). An index of 0.74 to 0.99 represents normal weight, while values of 1.00 or higher indicate overweight status.
What is the primary limitation of Body Mass Index?↓
BMI cannot evaluate visceral fat distribution, bone mineral density, age-related sarcopenia, or hydration status. For individualized clinical diagnosis, waist-to-hip ratio and DEXA scans provide greater physiological detail.
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Open calculator →Source Citation & Disclaimer
Informational tool only; not licensed tax, legal, or financial advice.