This BMI calculator follows adult category thresholds published by the CDC and explained by NIH/NHLBI. Use the number to frame a health conversation, then add waist measurements, body composition, medical history, and clinical context.
"BMI is useful because it is fast and standardized; it becomes risky when treated as a complete picture of health."
Adult cutoff
The visible categories are adult thresholds. CDC says adults 20 and older can use the adult BMI calculator, while ages 2–19 need the child and teen percentile tool.
Range awareness
The healthy range uses 18.5–24.9, then converts that BMI band into a weight range for your height. It is a reference band, not a prescription.
Context check
High muscle mass, pregnancy, older age, edema, or medical conditions can distort BMI. CDC explicitly describes BMI as a screening measure rather than a diagnostic test.
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.
Ideal weight is estimated using the Devine formula (1974), which uses height and gender. Body fat percentage is estimated using the Deurenberg formula (1991), which incorporates your BMI, age, and gender. Both are statistical estimates and may not reflect individuals with high muscle mass or special body compositions.
