To find the number of floor tiles needed for a room, multiply the length by the width of the room in feet, then divide that figure by the square footage of the tile to be used. It is a good idea to add an extra 10 percent to make sure there are enough tiles remaining to cover any measurement mistakes.
First, calculate the area of the room by multiplying length by width. If the room is 17 feet by 10 feet, the area is 170 square feet. (If the room is not perfectly rectangular, divide the room into rectangular sections, perform this step for each section, then add the area of these sections together.) Next, divide this figure by the area of the floor tile. If the floor tiles are one square foot apiece, this means 170 divided by one equals 170 floor tiles needed. If the tiles are smaller than a square foot, measure two sides of the tile, convert to decimals, and multiply to find the square footage of the tile. For example, tiles measuring half a foot along each side (.5 feet) have a square footage of .25 feet (.5 times .5 equals .25.) Then divide this figure by the square footage of your room (170 divided by .25 equals 680 floor tiles needed.)