Step 1
Take measurements of the room, or area of the room, in which you will be working. If the room is an odd shape, such as a room with a nook, divide the room and measure sections separately. This is necessary to complete your design plan. Measure both the length and width of the room, or area of the room, and record your measurements by drawing the room out on graph paper.
Step 2
Complete a design plan. This is only necessary if you want to create a design with your carpet tiles that uses more than one color or shape. Use the diagram you created on graph paper to create the design for the area the carpet tiles will cover.
Step 3
Determine total square footage of the room by multiplying room length by room width. For example, a room that measure 9 by 11 is 99 square feet.
Step 4
Determine square footage of an individual carpet tile. While the standard carpet tile size is 18 by 18 inches, you may find other sizes as well. To determine square footage, multiply the length by the width of the tile and divide the total by 144. For example, if a carpet tile is 18 by 18 inches, the tile is 2 1/4 square feet. If the carpet tile is 24 by 24 inches, the tile is 4 square feet.
Step 5
Calculate how many carpet tiles you need. Divide the total square feet of the room, or area of the room, by the square feet of one carpet tile to determine how many carpet tiles you need. For example, if the room is 99 square feet and the carpet tile is 18 by 18 inches, or 2 1/4 square feet, you need 44 carpet tiles, and if the carpet tile is 24 by 24 inches, or 4 square feet, you need 25 carpet tiles. If you are using more than one color, use your design plan to decide how many tiles of each color you need.