BMI360 - Free BMI Calculators for Adults, Kids & Military

BMI360 offers free Body Mass Index calculators built for different groups: standard BMI for adults, percentile-based BMI for children and teens, and Army-standard BMI for military personnel. There's also a reverse BMI calculator to find a target weight, and a pounds-to-kilograms converter.

Every calculator gives instant results with no signup required. Pick the tool that matches who you're calculating for below.

BMI is a quick screening measure, not a diagnosis — it doesn't account for muscle mass, bone density, or body composition directly. That's why BMI360 splits calculators by age group and context: growing children are measured against percentile charts rather than the fixed adult categories, and military fitness standards use their own thresholds. Using the calculator built for your situation gives a more meaningful result than a one-size-fits-all number.

Six tools live on this site. The adult BMI calculator uses the standard WHO/CDC weight categories (underweight, normal, overweight, obese). The kids BMI calculator compares a child's BMI against CDC growth-chart percentile bands for their exact age and sex, since a fixed BMI number means something different for a 7-year-old than a 17-year-old. The Army body composition calculator checks waist-to-height ratio against the current Army Body Composition Program standard. The reverse BMI calculator works backward from a target BMI and height to a target weight, and the pounds-to-kilograms converter handles plain unit conversion.

None of these tools are a substitute for a doctor's assessment — they're meant for quick, private screening, with a clear enough methodology that you can see exactly how each number was produced.