To work out the actual physical weight of a printed item without the aid of scales can be calculated very simply. Paper stock is measured by ‘grams per square metre.’
In order to calculate an individual non-printed item use the following formula.
width(m) x height(m) x stock(gsm) = grams
Example A: a flat sheet measuring 270x613mm printed on 90gsm Matt Art would be calculated by the following:
0.270 x 0.613 = 0.16551
x 90 grams per square metre
= 14.8959 grams
Example B: A standard A4 sheet of 80gsm Bond copier paper would be calculated:
0.210 x 0.297 = 0.06237
x 80 grams per square metre
= 4.9896 grams
Please note that this does not take into consideration ink; special finishes like foiling or spot UV. A general rule of thumb I use is with each process add 1 gram to the equation.
Example A = 14.8959gram + cmyk 2 sides(+1), spot UV(+1) and foiling(+1).
Total weight would be rounded to 18 grams.