Adult BMI US Units Calculator
Calculate adult body mass index from pounds and inches. BMI is a screening measure and does not by itself describe an individual's health.
Where your BMI falls
Your result is in the adult healthy weight screening category. The height-based weight range is an estimate, not a personal target. The tri-ponderal index uses cubed height; the BMI categories do not apply to it. Values outside 10–40 appear at the nearest end of the scale. BMI alone cannot diagnose health. CDC categories.
About this calculation
Body mass index (BMI) relates weight to height with one number. This tool is for adults aged 20 and older and reports BMI in kg/m². It can help start a conversation about weight status, but it does not diagnose health or measure body fat directly. Enter pounds and inches in the fields below.
Formula
BMI = 703 × weight(lb)/height(in)²
Worked example
With Weight: 165 lb, Height: 69 in, bmi is 24.363579 kg/m².
What BMI measures
The US-unit equation uses pounds and total inches of height with the conventional factor 703. Enter 5 feet 8 inches as 68 inches, not 5.8. At equal weight in pounds, a larger inch value lowers the calculated BMI because height is squared in the denominator.
Enter weight in pounds and height in inches. The calculator multiplies pounds by 703 and divides by the square of height in inches; 703 is the conventional conversion factor for these US units.
Adult BMI ranges
CDC adult screening categories are the same whether BMI was calculated in US or metric units. In this pounds-and-inches version, the 703 multiplier changes the arithmetic but not the category boundaries. A BMI of exactly 25.0 begins the overweight category.
- Underweight: below 18.5
- Healthy weight: 18.5 to below 25
- Overweight: 25 to below 30
- Obesity, class 1: 30 to below 35
- Obesity, class 2: 35 to below 40
- Obesity, class 3: 40 or higher
Worked example
An adult weighing 150 lb at 5 ft 8 in (68 in) has BMI = 703 × 150 ÷ 68² ≈ 22.8 kg/m². That falls in the adult healthy-weight range. The category is an interpretation of the number, not a medical conclusion.
How to interpret your result
Use the adult category as a first screening description, not a judgment about a person. Pounds and inches cannot show body-fat distribution or separate muscle from fat. Two adults with the same calculated BMI may have different waist measurements, medical histories, and clinical findings.
The adult US-unit tool does not interpret a child’s or teenager’s result. Ages 2–19 require BMI-for-age percentiles, using age and sex as well as height and weight. A pounds-and-inches entry can be mathematically computed for a young person, but the adult label displayed here would be inappropriate.
What the extra numbers mean
The height-based interval is first derived from the BMI boundaries 18.5 and 25 using height in meters, then converted back to pounds for this US-unit page. It is a mathematical illustration for the entered height. The upper bound is excluded at BMI 25, and neither endpoint is an individualized weight recommendation.
BMI Prime divides the calculated BMI by 25; it does not add another body measurement. For the tri-ponderal number, this page first converts pounds to kilograms and inches to meters, then divides kilograms by cubed height. Its kg/m³ result is not interpreted with the CDC BMI ranges and does not diagnose health.
Measurement and scope
Use a recent pound weight and convert feet plus inches to total inches before entering height. A person who is 5 feet 8 inches tall should enter 68, not 5.8 or 58. Small entry errors can move the result across a screening boundary. If pregnancy, unusual muscle mass, or illness affects interpretation, seek qualified individual advice.
Common questions
Is BMI a measure of body fat?
No. Pounds and inches calculate a ratio, not a direct measure of fat mass or body composition.
Does the same BMI range apply to children?
No. A child or teen needs age- and sex-specific percentiles even if their measurements are recorded in pounds and inches.
What does a BMI of 25 mean?
For an adult, a pounds-and-inches calculation equal to 25.0 starts the overweight screening category, but health assessment needs more information.
Is the weight interval a recommended target?
No. It converts an arithmetic BMI interval at your entered height into pounds, without considering individual health factors.
Can I share my calculation?
Yes. A share link contains your pound and inch entries and can be read by anyone who receives it.
Sources and references
Inputs
- Weight (lb)
- Height (in)