How do you figure the squares of siding on a house?

Question

Sqaures are 10ftx10ft

Answer 1

Yes a square is 100 Sq ft. Measure your house outside walls and determine the square ft you have to cover, divide by 100 at 10% for waste and you should be there

Answer 2

most siding installers just measure length time height to get square foot then divide by 100. they do not take off for windows or doors, this is the 10% scrap they ask you to purchase.