BMI Calculator

Calculate your Body Mass Index (BMI) using metric or imperial units. See your weight category and healthy weight range for your height.

Formula: BMI = Weight (kg) ÷ Height² (m²). BMI is a screening tool, not a diagnostic. It may not accurately reflect body fat for athletes, elderly, or children. Consult a healthcare professional for personalized advice.

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What is BMI?

BMI stands for Body Mass Index, which is a simple number calculation based on a person's weight and height. It is used globally by doctors and health organizations as a quick screening tool to see if you are a healthy weight for how tall you are. This free tool lets you calculate your exact BMI in both metric and imperial measurements.

The Official BMI Categories

The World Health Organization (WHO) divides BMI scores into different categories to help assess health risks:

Underweight

BMI: Under 18.5

Normal Weight

BMI: 18.5 to 24.9

Overweight

BMI: 25.0 to 29.9

Obesity

BMI: 30.0 and higher

Why BMI is Not Perfect

While BMI is a fast and useful tool for large populations, it does not tell the whole story about an individual's health. You should always talk to a medical professional. Here is why BMI can sometimes be misleading:

  • Muscle Mass: Muscle weighs more than fat. Athletes and bodybuilders often score as "Overweight" or "Obese" even if they have very little body fat.
  • Age & Gender: BMI does not account for the fact that women naturally carry more body fat than men, or that older adults lose muscle as they age.
  • Body Shape: BMI cannot tell where fat is stored. Belly fat is far more dangerous to heart health than thigh fat.

Other Fun Utility Tools

If you found this tool helpful for personal tracking, you might also like checking your exact age in days with our Exact Age Calculator.

Body Mass Index FAQ

How is BMI calculated?

The formula for BMI is your weight in kilograms divided by the square of your height in meters (kg/m²). Our tool does this math for you automatically.

Is this calculator safe for children?

No. The standard BMI formula on this page is strictly for adults (ages 20 and older). Children and teenagers require a special BMI percentile chart that accounts for their rapid growth.

What is a healthy BMI for older adults?

Many experts suggest that for older adults (over 65), a slightly higher BMI (between 25 and 27) might actually be healthier and offer protection against nutritional deficiencies.

Should I panic if my BMI is high?

Absolutely not. BMI is just one data point. Your blood pressure, cholesterol levels, diet, and exercise habits are far more important indicators of your overall health. Talk to your doctor to understand the full picture.