Wing loading is typically expressed as ounces per square foot, but all too often we think of wing area in square inches and weight in pounds. Normally to find the wing loading you would multiply the weight in pounds by 16 to get ounces. Then you would divide the area in square inches by 144 to get square feet. Then you would divide the weight by the area to get the wing loading in ounces per square foot. But there is a simple way to cut out some steps. You need to multiply 16 by 144 to get a handy single step conversion factor.

Weigh the plane in pounds. One easy way to do this is with a bathroom scale that displays pounds and decimals of pounds, which is what most bathroom scales do. Step on the scale with the plane, and then without it, and note the difference. That’s a lot easier than trying to balance a plane on a scale by itself. (This is also a good way to weigh a friendly dog, but not a squirmy one.) Multiply the weight by 2304. When you get the result, divide it by the area in square inches. The final answer will be ounces per square foot.

Example:

My bathroom scale says my plane weighs 6.8 pounds. Multiplying the span by the chord gave me a wing area of 850 square inches.

6.8 x 2304 = 15667.2

15667.2 ÷ 850 = 18.432

My airplane has a wing loading of about 18½ ounces per square foot. (close enough)