BMI Calculator
Body Mass Index & Healthy Weight Range
Frequently Asked Questions
- Body Mass Index uses weight divided by height squared: kg / m² for metric inputs, or 703 × lb / in² for imperial inputs. The CDC adult BMI calculator uses the same adult screening concept.
- For adults, the CDC lists underweight as below 18.5, healthy weight as 18.5 to 24.9, overweight as 25.0 to 29.9, and obesity as 30.0 or greater. See the official CDC adult BMI categories.
- No. BMI is a screening measure, not a diagnosis. The CDC says it should be interpreted with medical history, health behaviors, physical exam findings, and lab results. The NIH/NHLBI BMI page also notes that BMI does not account for muscle mass, bone density, or body composition.
- This calculator uses adult BMI cutoffs. For ages 2 through 19, BMI is interpreted by sex-specific BMI-for-age percentiles, so use the official CDC Child and Teen BMI Calculator.
- The range uses the adult healthy BMI band of 18.5 to 24.9 and solves the formula backward for your entered height. It is a planning estimate, not a personalized medical target. The WHO explains that BMI over 25 is considered overweight and over 30 obese in its obesity overview.