when I estimate jobs, I used a steel suppliers weight book, that's how the supplier figures the weigh of the material you buy, and I usually never actually weighed material when I sold it to walk in customers. just use the theoretical weight that is in 40.8/144the books that I had copied to an easy to read chart under the plastic of my desk. but if you remember a few simple things you can figure the weight of anything with a cheap calculator. a square foot of 1/8th or 11 ga is 5.1, 3/16 or 7 ga is 7.5, 1/4 or 4 ga is 10.2 lbs. just figure the square feet, length times width divided by 144 times the weight of that particular thickness of steel, so 1 inch would be 40.8 divided by 144= .2833333333333lbs. times 16, the ounces in a lb, =4.5333 ounces.