For the sake of argument lets say your shed has 8 ft walls.

Not counting "cutouts" for openings: 16+16+20+20 * 8 = 576 square ft.

Lets also say your shed has a gable-style roof and the peak is 14 ft above the floor...

That would make the peak 6 feet taller than the 8ft walls so the formula to figure out the square footage of the "triangle" would be width times half the height of the triangle or 20 * 3 * 2 = 120 square ft. (you would have at least 2 walls with peaks)

Your total siding = 696 square ft.

One "square" = 100 square ft. So to determine the number of "square" required simply divide your total square footage by 100...

Bottom line, even rounded up, without any provision for "cutouts" you need 7 square of siding...

Not counting "cutouts" for openings: 16+16+20+20 * 8 = 576 square ft.

Lets also say your shed has a gable-style roof and the peak is 14 ft above the floor...

That would make the peak 6 feet taller than the 8ft walls so the formula to figure out the square footage of the "triangle" would be width times half the height of the triangle or 20 * 3 * 2 = 120 square ft. (you would have at least 2 walls with peaks)

Your total siding = 696 square ft.

One "square" = 100 square ft. So to determine the number of "square" required simply divide your total square footage by 100...

Bottom line, even rounded up, without any provision for "cutouts" you need 7 square of siding...