BMI Calculator — Imperial (lb, in)
The imperial BMI page works in pounds and inches, the everyday units in the United States. Because the index is defined metrically, it multiplies the pounds-over-inches-squared ratio by 703 — the conversion factor BMI = 703 × lb / in² — so you never have to translate to kilograms or meters yourself. Enter a weight in pounds and a height in inches to see your index, your WHO category, and the pound weight band that keeps BMI between 18.5 and 24.9.
Body mass index estimate
Estimated BMI
22.7
Normal weight
Reference for your height
Healthy weight band (lb) for BMI 18.5–24.9 at the height entered.
BMI = 703 × lb / in², classified against the WHO adult categories. It is a screening estimate that ignores muscle, frame, age, and sex — not a medical diagnosis or dietary advice. Consult a healthcare professional before acting on this number.
Why the 703 factor
BMI is defined metrically, so to use pounds and inches the formula adds a conversion factor: BMI = 703 × lb / in². You enter weight in pounds and height in inches, the tool divides weight by height squared, then multiplies by 703 to rescale the result into the standard metric index. This lets you stay in the everyday United States units without translating to kilograms or meters yourself.
The number you get matches the metric page exactly and uses the same WHO cut points. It remains a screening estimate that ignores muscle, frame size, age, and sex, so read the category as a signal to look closer, not a measure of body fat.
Questions
- What is the imperial BMI formula?
- BMI = 703 × lb / in². You divide weight in pounds by height in inches squared, then multiply by 703. The 703 factor converts the pounds-and-inches ratio into the same value the metric kg / m² formula produces.
- Why multiply by 703 instead of just dividing pounds by inches?
- Because BMI is defined in kilograms and meters. Dividing pounds by inches squared gives a different scale, so the 703 factor rescales it to the metric index. Without it the number would not match the standard WHO categories.
More ways to use this calculator
Start with the main bmi calculator or compare the other published scenarios.
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