Enter your height in feet and inches and weight in pounds — get your BMI instantly.
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In the US, most people know their height in feet and inches and their weight in pounds. BMI works fine with those units — you just need the imperial formula: BMI = 703 × weight (lbs) ÷ height (in)². That 703 is a conversion factor bolted on so the result matches the metric answer.
Quick example: a 5’10” (70 inches) adult weighing 170 pounds. Square the inches: 70 × 70 = 4900. Divide weight by that: 170 ÷ 4900 = 0.0347. Multiply by 703: BMI 24.4. That’s right at the top of the healthy range. The calculator above does this instantly, so you don’t have to.
One thing that trips people up in imperial: the inches. Enter your total height correctly — six feet is 72 inches, not 6. The calculator has separate fields for feet and inches so you don’t have to do that math. It also accepts fractional inches (5.5 for 5½) if you want to be precise.
A few imperial BMI reference points that are worth knowing: a healthy adult at 5’0” weighs between 97 and 128 lbs. At 5’6”, that range is 118 to 155 lbs. At 5’10”, it’s 132 to 173 lbs. At 6’0”, it’s 140 to 184 lbs. Anywhere inside those brackets is BMI 18.5 to 24.9, which is the WHO healthy range. The tool above will give you the exact pound range for your height.
If you prefer metric, our metric BMI calculator uses kilograms and centimeters. Different formula on paper, same answer on the scale. And if you want more context on what your number actually means — muscular athletes especially — read our full BMI guide, which covers the limitations and better alternatives like waist-to-height ratio.
BMI = 703 × weight (lbs) ÷ height (inches)². Multiply your weight in pounds by 703, divide by your height in inches squared. The 703 factor is what makes the imperial result match the metric one.
A healthy BMI is 18.5 to 24.9. In pounds, that’s roughly 97–128 at 5’0”, 118–155 at 5’6”, 132–173 at 5’10”, and 140–184 at 6’0”. The calculator above gives you the exact range for your height.
Convert your height to inches (feet × 12 + extra inches). Square it. Divide your weight in pounds by that number. Multiply by 703. Example: 5’9” = 69 inches; 69² = 4761; 160 lbs ÷ 4761 × 703 = BMI 23.6.
It’s a unit conversion constant. Metric BMI is kg/m². To use pounds and inches directly, you need to convert lb to kg (÷ 2.2046) and inches to meters (× 0.0254), which — after squaring the meter conversion — collapses to a single multiplier of about 703.
No — the two formulas produce identical results to within rounding. Imperial is just clunkier to compute mentally, which is why calculators (like this one) exist.
We wrote a plain-English guide that covers the history, the limits, and what to actually do about your number.
Read the BMI guide →