How do i convert square feet to a percentage?

Percentages are used when comparing two things. I'll give you an example: You have a piece of carpet and a room to put it in, and you want to know what percentage of the floor the carpet will cover. The carpet is 100 square feet, and the room is 150 square feet. The formula is: (square footage of the carpet / square footage of the room) x 100 100/150 is .6667; multiply that by 100 to get 66.67 percent. If you want to carpet the room wall-to-wall, you need more carpet. OTOH, if you have a 200 square foot carpet and a 100 square foot room... (200/100) x 100 = the carpet is 200 percent of the size of the room, and you'll have to cut half of it off.