BMI Calculator
Calculate your Body Mass Index (BMI) using metric or imperial units.
Why Use This Calculator?
Determine your Body Mass Index (BMI), a standardized measure used by health professionals globally to assess whether you are at a healthy weight for your height.
Recommended Workflow
Select System
Choose between Metric (kg/cm) or Imperial (lbs/in) units.
Enter Height
Input your exact height.
Enter Weight
Input your current weight.
Check Category
Review your BMI score and the corresponding health category.
How the BMI Calculator Works
Body Mass Index (BMI) is a simple mathematical formula used to estimate whether a person has a healthy body weight for their height. The calculation divides your weight by the square of your height, providing a numerical value that corresponds to different weight categories.
Understanding Your Results
- Underweight (BMI < 18.5): May indicate malnutrition, an eating disorder, or other health issues.
- Healthy Weight (BMI 18.5 - 24.9): Generally associated with the lowest risk of weight-related health problems.
- Overweight (BMI 25.0 - 29.9): Carries a moderately increased risk of developing cardiovascular issues.
- Obese (BMI ≥ 30.0): Associated with a significantly higher risk of type 2 diabetes, high blood pressure, and heart disease.
Example Calculation
Let's look at an adult who is 1.75 meters tall and weighs 70 kilograms:
- Height: 1.75 m (squared = 3.0625)
- Weight: 70 kg
- Math: 70 / 3.0625
- Result: 22.86 (Healthy Weight)
In the imperial system, the formula is (weight in lbs / height in inches squared) × 703.
Common Mistakes to Avoid
Treating BMI as a Diagnosis
BMI is an estimate, not a diagnostic tool. It does not measure body fat directly or consider your overall health markers.
Ignoring Muscle Mass
Because muscle is denser than fat, athletes and bodybuilders often fall into the "Overweight" or "Obese" categories despite having very low body fat percentages.
Related Health Tools
This calculator provides estimates for informational purposes only. Please read our Medical Disclaimer.
Common Mistakes to Avoid
- •Using BMI as the sole indicator of health without considering muscle mass.
- •Entering height or weight in the wrong unit system.
- •Applying adult BMI ranges to children or teenagers.
What to do next?
How it works (Formula)
Metric: BMI = weight(kg) / height(m)², Imperial: BMI = (weight(lbs) / height(in)²) × 703
Real-World Examples
BMI for an Average Height Male
Inputs (The Math)
- Height5 ft 9 in (175 cm)
- Weight160 lbs (72.5 kg)
Outputs (The Result)
- BMI Score23.6
- CategoryHealthy Weight
Why it works this way
A BMI of 23.6 falls comfortably within the healthy weight range (18.5 - 24.9). This means their weight is generally proportionate to their height according to standard medical guidelines.
- Individual is an adult.
- Does not account for extreme muscle mass.
BMI vs. BMR: Which Should You Use?
Understand the difference between Body Mass Index and Basal Metabolic Rate.
| Feature | BMI Calculator | BMR Calculator |
|---|---|---|
| Primary Purpose | Assesses weight categories (underweight, normal, overweight, obese) | Estimates baseline daily calorie burn at rest |
| Required Inputs | Height, Weight | Height, Weight, Age, Gender |
| Limitations | Does not account for muscle mass vs. fat | Only estimates resting calories, not total daily expenditure (TDEE) |
Frequently Asked Questions
What is a healthy BMI?
For most adults, an ideal BMI is in the 18.5 to 24.9 range.
Is BMI accurate for athletes?
BMI can be misleading for athletes with high muscle mass, as muscle is denser than fat. A muscular person might have a high BMI without having high body fat.
Are there age limits for BMI?
The standard adult BMI categories apply to men and women aged 20 and older. For children and teens, age- and sex-specific percentiles are used instead.
Medical Disclaimer
This calculator provides an estimate for educational purposes only. It is not intended to provide medical advice, diagnosis, or substitute for professional medical judgment.
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