How to Use BMI Calculator
Follow these steps, then review the result and the limitations below:
- Enter your body weight in kilograms (kg) in the "Weight" field.
- Enter your height in centimeters (cm) in the "Height" field.
- Click "Calculate" to compute your Body Mass Index score and World Health Organization (WHO) weight classification.
- Review your BMI score, weight category, and the calculated BMI reference weight range for your height.
Practical Worked Example
Entering a weight of 70 kg and a height of 175 cm computes a BMI Score of 22.9 (Healthy weight) with an BMI reference weight range of 56.7 kg – 76.3 kg for that height.
Key Features & Capabilities
- Instant calculation based on official World Health Organization (WHO) clinical classifications.
- Calculates personalized BMI reference weight target boundaries for your specific height.
- Shows a text category based on the unrounded BMI and a score rounded to one decimal place.
- The calculation code runs locally in your browser; avoid entering sensitive health information on shared devices.
Read BMI as a screening calculation
BMI is weight in kilograms divided by height in metres squared. For 70 kg and 1.75 m, the calculation is 70 / 3.0625, or approximately 22.9. The category uses the unrounded result, which can matter near a boundary.
This page applies a simple adult classification. It cannot assess an individual's health, body composition, pregnancy, growth, or medical history. It is not a weight-loss prescription. Children and adolescents require age-appropriate assessment.
Avoid unit errors
Enter centimetres rather than metres in the height field: 175 is the intended input for someone 1.75 m tall. Check the units on your scale before entering weight. Zero or negative measurements are rejected.
The displayed reference weight interval is calculated from BMI boundaries, not from a personal clinical assessment. Discuss health concerns with a qualified professional rather than using this number as a target.
How It Works (Technical Overview)
BMI = weight in kilograms / (height in metres squared). The displayed score is rounded to one decimal, while the category uses the unrounded value: below 18.5, below 25, below 30, or 30 and above. The reference interval is calculated from BMI values 18.5 and 24.9, not from an individual health assessment.
Real-World Use Cases & Applications
- Fitness & wellness: Individuals tracking weight loss, fitness journeys, and general body composition trends.
- Health planning: Setting realistic, healthy body weight target ranges in consultation with healthcare professionals.
- Athletic training: Establishing baseline weight metrics for sports categories and training programs.
Privacy, Security & Accuracy
BMI is a statistical health indicator and does not directly measure body fat percentage, bone density, or muscle distribution. It should not replace clinical medical evaluation.
Pro Tips for Best Results
Track your BMI alongside waist circumference and overall physical activity levels for a more comprehensive picture of your metabolic health.
Frequently Asked Questions
What is considered a healthy BMI score?
According to the World Health Organization, a BMI score between 18.5 and 24.9 is classified as the standard healthy weight range for adult men and women.
Does BMI distinguish between muscle mass and fat?
BMI is a generalized screening metric based on height and weight. Because muscle is denser than fat, muscular athletes and bodybuilders may register higher BMI scores without excess body fat.
Is BMI suitable for children and teenagers?
Adult BMI formulas apply to individuals aged 18 and older. Children and teens use BMI-for-age percentile charts that account for ongoing growth and biological development.
How can I convert pounds (lbs) and inches into kg and cm?
You can use our free Unit Converter tool to easily convert pounds to kilograms (1 lb ≈ 0.453 kg) and feet/inches to centimeters (1 inch = 2.54 cm).
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