Calculate your Body Mass Index instantly. Supports metric and imperial units.
Enter your weight and height on the left to see your BMI result here.
A BMI between 18.5 and 24.9 is considered normal weight for most adults.
BMI is a useful screening tool but has limitations — it doesn't account for muscle mass, bone density, or body fat distribution. Always consult a doctor for medical advice.
BMI = weight(kg) ÷ height(m)². In imperial: BMI = (weight(lbs) ÷ height(in)²) × 703.
Get your BMI and category in seconds — metric, imperial, or mixed units. No sign-up.
Often not. Muscle weighs more than fat, so resistance-trained athletes commonly land in the overweight range despite low body-fat percentages. Pair BMI with a body composition test if you train heavily.
For most adults, 18.5 to 24.9 is classified as healthy. In adults over 65, slightly higher BMIs (up to about 27) are associated with the best longevity outcomes.
Whichever you're more comfortable measuring in. The numerical BMI is identical between the two — the conversion factor is built in.
Every few months is plenty if you're a healthy weight. If you're actively trying to gain or lose, weekly checks are sufficient — daily fluctuations are mostly water and digestion.
Yes. It doesn't distinguish muscle from fat, doesn't account for fat distribution (visceral vs subcutaneous), and varies in clinical meaning across ages and ethnicities. Treat it as one signal, not a verdict.
BMI is the most widely cited health metric in the world and the most-misunderstood. The ConvertDox BMI Calculator gives you the number quickly and — importantly — pairs it with the category and a clear interpretation, so you don't leave wondering what 24.7 actually means. The calculator supports both metric (kilograms and centimetres) and imperial (pounds and feet/inches) units, and you can mix and match if you happen to know your weight in kilos but your height in feet. The math is identical between the two: BMI = weight in kilograms divided by height in metres squared, with a 703 conversion factor when inputs are in pounds and inches. Because the calculation runs in your browser, your weight and height are never sent over the network — relevant if you'd rather not see your stats logged in a third-party analytics dashboard. The tool deliberately includes context around the result rather than just spitting a number: the category (underweight / normal / overweight / obese), what the category is generally taken to mean, and a reminder that BMI has known limitations for athletes, the elderly, pregnant women, and people of different ethnic backgrounds. For a deeper look at the formula and the alternatives, our companion BMI guide walks through everything in detail.