BMI Calculator – Addition.site
A quick, free, and fully‑online tool for measuring Body Mass Index (BMI).
Enter your weight in kilograms and height in centimeters, click Calculate, and the page instantly shows your BMI value (rounded to one decimal place) and the corresponding health category (Underweight, Normal, Overweight, Obese). The result can be copied to the clipboard or shared on X (formerly Twitter) with a single click.
How to Use the Calculator
- Open the page –
https://addition.site/bmi-calc.html. - Enter your weight – the field labeled weight (kg) accepts decimal values (e.g.,
70.5). - Enter your height – the field labeled height (cm) expects a whole number or decimal (e.g.,
170). - Click the “calculate” button – the script runs the BMI formula:
[ \text{BMI} = \frac{\text{weight (kg)}}{(\text{height (m)})^2} ]
Height is automatically converted from centimeters to meters. - View the result – the value appears in the read‑only input field labeled result.
- Copy the value – click the result field; a “Copied!” message confirms the clipboard action.
- Share on X – press the 𝕏 button to open a pre‑filled tweet with your BMI and category.
Understanding BMI
- Body Mass Index (BMI) is a simple numeric measure that relates weight to height.
- It is widely used by clinicians and public health authorities to screen for weight‑related health risks.
- The formula is: BMI = weight (kg) ÷ [height (m)]².
- Results are reported as a single number (e.g., 22.4) and interpreted against standard thresholds.
BMI Categories (World Health Organization)
| Category | BMI Range | Interpretation |
|---|---|---|
| Underweight | < 18.5 | Potential nutrient deficiency or low body fat. |
| Normal | 18.5–24.9 | Healthy weight for most adults. |
| Overweight | 25.0–29.9 | Increased risk of cardiovascular disease. |
| Obese | ≥ 30.0 | Higher risk of chronic conditions (diabetes, hypertension). |
Use Cases
- Health screening – Quick check before a medical appointment.
- Weight management – Track BMI changes while following a diet or exercise program.
- Fitness planning – Use BMI as one of several metrics to gauge overall fitness.
- Educational tool – Demonstrate how weight and height interact in a simple formula.
Limitations & Caveats
- BMI does not differentiate between muscle and fat mass.
- It may misclassify athletes or very muscular individuals as overweight/obese.
- Ethnic and age variations exist; the WHO thresholds are general guidelines.
- Always consult a healthcare professional for personalized advice.
Privacy & Security
- No personal data is stored or transmitted beyond the browser session.
- The calculator runs entirely client‑side in JavaScript; no server‑side processing is involved.
Share Your Results
- The X button opens a tweet draft: “My BMI is 23.1 – Normal. Check out this free BMI calculator: https://addition.site/bmi-calc.html”.
- Copying the result is useful for sharing with friends, family, or health apps that accept BMI input.
Try It Now
Simply type your weight and height, hit Calculate, and instantly see your BMI and health category. Use the copy or X share features to keep track or spread the word. The tool is responsive, works on mobile and desktop, and is completely free to use.
Start measuring your health today with the Addition.site BMI Calculator – fast, accurate, and free.