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Body Composition Tool

BMI Calculator

A quick weight-to-height check. Useful as a starting point — not the whole story.

BMI Categories

CategoryBMIRisk
Underweight< 18.5Moderate
Healthy Weight18.5–24.9Lowest
Overweight25.0–29.9Increased
Obese Class I30.0–34.9High
Obese Class II35.0–39.9Very High
Obese Class III≥ 40.0Extreme

Source: WHO

What your BMI result actually means

BMI (Body Mass Index) divides your weight in kg by the square of your height in metres. It's fast, requires no equipment, and gives a rough indication of whether weight is in a healthy range. It's also genuinely limited: it can't distinguish muscle from fat, doesn't account for age or sex differences in body composition, and tends to misclassify muscular athletes as overweight.

Use BMI as one data point, not a verdict. Pair it with body fat percentage and waist-to-height ratio for a more complete picture. Read more: What Is BMI and When Should You Actually Care?

FAQs

What is a healthy BMI?

18.5–24.9 for most adults. Research suggests people of Asian descent face higher health risks at lower BMI values, and the WHO uses adjusted cutoffs for some populations.

Is BMI accurate for athletes?

Not really. A muscular person can have a BMI of 27 and be in excellent health. BMI can't tell the difference between 10 kg of fat and 10 kg of muscle. Body fat percentage is a much better measure for anyone who trains seriously.

What should I do if my BMI is high?

Talk to a doctor — BMI is a screening signal, not a diagnosis. Your GP will look at blood pressure, blood sugar, cholesterol, family history, and other factors before drawing any conclusions.