BMI Calculator
Use our free online BMI Calculator to perform fast, accurate calculations with instant formulas, step-by-step arithmetic, and verified reference benchmarks.
Instant BMI Calculator
Healthy weight range: 60.0 kg – 80.7 kg
How to Calculate: The BMI Calculator Formula
Body Mass Index is calculated by dividing body mass in kilograms by the square of body height in meters. For US Imperial units: BMI = [weight (lbs) / (height (in))²] × 703.
Step-by-Step Calculation Guide
- Measure your exact height without shoes and record your current body weight.
- Convert height to meters (or inches for imperial) and weight to kilograms (or pounds).
- Square the height value (height × height).
- Divide body weight by the squared height value (and multiply by 703 if using pounds and inches).
Practical BMI Calculator Examples
Height: 180 cm (1.80 m), Weight: 75 kg.
Height: 5 ft 10 in (70 in), Weight: 185 lbs.
WHO & CDC Adult BMI Classification Benchmark
Official reference values and benchmark classifications based on standard institutional guidelines.
| BMI Range (kg/m²) | Weight Classification | Health Risk Level |
|---|---|---|
| Less than 18.5 | Underweight | Elevated |
| 18.5 – 24.9 | Normal (Healthy) | Lowest |
| 25.0 – 29.9 | Overweight | Increased |
| 30.0 – 34.9 | Obesity Class I | High |
| 35.0 – 39.9 | Obesity Class II | Very High |
| 40.0 and above | Obesity Class III (Severe) | Extremely High |
Frequently Asked Questions about BMI Calculator
What is a healthy BMI score for men and women?
According to the World Health Organization (WHO) and CDC, a healthy BMI score for both adult men and women ranges between 18.5 and 24.9.
Does BMI distinguish between muscle and body fat?
No. BMI only measures body mass relative to height. Muscular athletes often register as overweight or obese despite possessing low body fat percentages.
How often should you calculate your BMI?
Checking your BMI every 1 to 3 months is sufficient for tracking general weight maintenance, fitness programs, or nutritional progress.
What is the formula for calculating BMI in pounds and inches?
The imperial formula is: BMI = (Weight in pounds / (Height in inches)²) × 703.