BMI Calculator
Verified Calculation Engine
The online BMI Calculator helps you calculate instantly and solve problems related to Body Metrics. This tool provides accurate results using standard formulas and step-by-step calculation; you can view the formula with example in the calculator where available. Whether you are a student, teacher, or professional, this calculator simplifies complex calculations and saves time. Enter the required values below and get instant results. Results are shown clearly, with optional step-by-step explanation where applicable. The tool is free to use and works in any modern browser—no download or installation required. Bookmark this page for quick access whenever you need reliable Health Fitness calculations.
Calculate Body Mass Index (BMI) and determine weight category. Supports multiple units (kg, lbs, cm, inches, feet, meters)
BMI = weight (kg) / height (m)²
Body Mass Index is weight divided by height squared. Units are automatically converted to kg and meters.
- Adult BMI category cut-offs are used for labeling.
- Weight and height are converted to kilograms and meters before calculation.
- BMI is a screening index, not a clinical diagnosis.
Inputs
Results
Worked Examples
Example 1: Normal weight (kg and cm)
Calculate BMI for 70 kg person with 175 cm height
- weight: 70
- weightUnit: kg
- height: 175
- heightUnit: cm
- bmi: 22.9
- category: Normal weight
Example 2: Overweight (lbs and inches)
Calculate BMI for 187 lbs person with 67 inches height
- weight: 187
- weightUnit: lbs
- height: 67
- heightUnit: inches
- bmi: 29.3
- category: Overweight
About this calculator
Overview
This BMI calculator converts your weight and height into Body Mass Index and maps the result to a common adult BMI category label.
When to use
Use it for a quick, standardized height–weight index. It is a screening metric, not a diagnosis of health or body composition.
Inputs explained
- Weight [required]
- Weight Unit [required]
- Height [required]
- Height Unit [required]
Formula / method
BMI = weight (kg) / [height (m)]² after unit conversion. Categories commonly use adult cut-offs such as underweight (<18.5), normal (18.5–24.9), overweight (25–29.9), and obesity (≥30).
Worked example
Example: 70 kg and 175 cm → height = 1.75 m → BMI = 70 / (1.75²) ≈ 22.9 (normal weight category on the standard adult scale).
Interpreting results
BMI does not distinguish muscle from fat. Athletes, older adults, children, and some ethnic groups may need clinical interpretation beyond this index.
Assumptions
- Adult BMI category cut-offs are applied.
- Inputs are converted to kilograms and meters before calculation.
Limitations
- Not a medical assessment of fitness, nutrition, or disease risk.
- Not appropriate as the sole measure for children or pregnancy without clinical guidance.
Important note
Informational and educational only. Not medical advice, diagnosis, or a substitute for clinical care. Consult a qualified clinician for health decisions.
How to Use This Calculator
- Enter the required values in the input fields.
- Click the Calculate button.
- View the computed result instantly.
Formula Used
BMI = weight (kg) / [height (m)]² after unit conversion. Categories commonly use adult cut-offs such as underweight (<18.5), normal (18.5–24.9), overweight (25–29.9), and obesity (≥30).
Example Calculation
Example: 70 kg and 175 cm → height = 1.75 m → BMI = 70 / (1.75²) ≈ 22.9 (normal weight category on the standard adult scale).
Frequently Asked Questions
What is BMI Calculator?
- This BMI calculator converts your weight and height into Body Mass Index and maps the result to a common adult BMI category label.
How does BMI Calculator work?
- BMI = weight (kg) / [height (m)]² after unit conversion. Categories commonly use adult cut-offs such as underweight (<18.5), normal (18.5–24.9), overweight (25–29.9), and obesity (≥30).
Why use this Health Fitness calculator?
- Use it for a quick, standardized height–weight index. It is a screening metric, not a diagnosis of health or body composition.