BMI Calculator — Check Your Body Mass Index Free | CalculHub
BMI Calculator
What is BMI?
BMI (Body Mass Index) is a numerical measure of body fat based on your height and weight. It is widely used by doctors and health professionals to screen for weight categories — underweight, healthy weight, overweight, and obesity — that may lead to health problems. BMI is not a direct measure of body fat but serves as a useful, inexpensive screening tool for the general population.
BMI applies to adult men and women of all body types. For children and teenagers, age and sex-specific percentiles are used instead.
How to Use This BMI Calculator
- Enter your height in centimetres (e.g., 175 cm).
- Enter your weight in kilograms (e.g., 70 kg).
- Click the Calculate BMI button.
- Your BMI score and category (Underweight / Normal / Overweight / Obese) will appear instantly.
- Use the BMI scale bar to see where your result falls visually.
BMI Formula
- Weight — your body weight in kilograms
- Height (m) — your height in metres (e.g., 175 cm = 1.75 m)
Example: A person weighing 70 kg at 1.75 m has a BMI of 70 ÷ (1.75 × 1.75) = 22.86 — in the Normal range.
Frequently Asked Questions
What is a healthy BMI range?
A BMI between 18.5 and 24.9 is considered healthy for adults. Below 18.5 is underweight, 25–29.9 is overweight, and 30 or above is classified as obese.
Is BMI accurate for everyone?
BMI is a screening tool, not a diagnostic one. It may overestimate body fat in athletes (who have more muscle) and underestimate it in older adults who have lost muscle mass. Consult a doctor for a complete health assessment.
What BMI is considered obese?
A BMI of 30 or above is classified as obese. A BMI of 40 or above is classified as Class III (severe) obesity. Obesity is associated with increased risk of type 2 diabetes, heart disease, and other conditions.
Can I use this calculator for children?
This calculator uses the standard adult BMI formula. For children and teenagers (ages 2–19), a separate BMI-for-age percentile chart is recommended, as growth patterns differ significantly.