How do I use the BMI Calculator?
Enter your values in the fields and the result updates instantly as you type.
BMI Calculator
Calculate your Body Mass Index (BMI). Enter your values, review the formula, and use the worked result as a quick check for everyday planning.
BMI Calculator
Calculate your Body Mass Index (BMI).
Unit: kg
Unit: cm
Results
BMI
22.857143
Category
Normal weight
Formula: BMI = weight(kg) / height(m)²
Disclaimer: BMI is a screening estimate, not a diagnosis. It may be less accurate for athletes, older adults, pregnant people, and people with high muscle mass. For medical decisions, talk to a healthcare professional.
Understanding Your BMI Score
Body Mass Index (BMI) is a screening tool that estimates body fat based on height and weight. This calculator gives you the numeric value and its corresponding weight category using the standard World Health Organization classification.
Formula
The formula is BMI = weight(kg) ÷ height(m)². Enter your weight in kilograms and height in centimeters. The calculator converts cm to meters automatically, then divides weight by the square of height.
Worked example
A person weighing 70 kg and 175 cm tall has a BMI of 22.86 — in the Normal weight range (18.5 to 24.9). BMI below 18.5 is classified as Underweight; 25.0 to 29.9 as Overweight; 30.0 and above as Obese.
Practical guidance
BMI is a screening tool, not a diagnosis
BMI does not distinguish between muscle and fat. Athletes with high muscle mass may have a high BMI but low body fat. Older adults may have normal BMI but higher body fat percentage. Always discuss health concerns with a healthcare professional.
Weight categories are population-based
The standard BMI categories (underweight, normal, overweight, obese) are based on population studies. Different ethnic groups may have different risk thresholds. This calculator uses the WHO standard categories.
Frequently asked questions
What formula does this calculator use?
BMI = weight(kg) / height(m)²
Can I use decimal values?
Yes. Decimal inputs are supported for most calculators. Integer-based tools use rounded integer values where appropriate.
Is this calculator free?
Yes. CalcuNimble calculators are free and optimized for fast everyday use.