Body Mass Index (BMI) is a simple ratio of weight to height that is often used as a screening tool to group adults into underweight, normal, overweight and obese categories.

Is BMI a perfect measure of health?

No. BMI does not distinguish between muscle and fat, and it may not reflect body composition accurately for athletes, older adults or people with certain medical conditions. Treat it as a starting point, not a diagnosis.

Does this BMI calculator store my data?

No. All calculations take place in your browser. CalcWarehouse.com does not send your height or weight to any server.

BMI Calculator – Check Your Body Mass Index

This BMI calculator uses the standard metric formula to estimate your Body Mass Index based on weight in kilograms and height in centimeters. It also labels your result as underweight, normal, overweight or obese according to common adult BMI ranges. Use it as a quick educational tool to discuss your health goals with a doctor or nutrition professional.

BMI Calculator

Estimate your Body Mass Index (BMI) using metric units. BMI is a simple screening measure that relates weight to height, commonly used to group adults into underweight, normal, overweight and obese categories.

Understanding the BMI formula

BMI is calculated by dividing your weight in kilograms by your height in meters squared. In symbols:

BMI = weight (kg) ÷ (height (m))²

The calculator first converts your height from centimeters to meters by dividing by 100. It then squares the height and performs the division. The resulting BMI value is rounded to one decimal place for readability and compared against the standard ranges to assign a category.

Using BMI as one input in a broader health conversation

BMI is popular because it is quick and easy to calculate, requiring only basic measurements. However, it is important to treat it as one input among many when thinking about health. People with high muscle mass, such as athletes, may have a high BMI but low body fat. Older adults may lose muscle mass without a large change in BMI. Certain medical conditions and medications can also influence weight distribution in ways that BMI does not capture.

When you use this BMI calculator, treat the result as a starting point for questions rather than a final verdict. If your BMI is outside the "normal" range, consider discussing it with a doctor, dietitian or other qualified professional who can interpret it in the context of your medical history, lab results, lifestyle and goals. They may use additional measurements such as waist circumference, body composition analysis or blood markers to provide a fuller picture.

One practical use of BMI is tracking changes over time. By keeping records of your height and weight, you can see whether your BMI is moving toward a target range as you adjust your habits. The BMI calculator on CalcWarehouse.com makes it simple to re-run the numbers periodically without signing in or installing an app. Combine this with the calorie calculator and other tools to create a more comprehensive view of your health journey while keeping sensitive data on your own device.