Ceramic tiles come in many sizes and 12 by 12 inch ceramic tiles add a durable and attractive appearance to a room. Normally tiles of this sort are used for flooring and are suitable for almost any room. However, before you head off to the building supply store to select and buy your tiles, stop and take some careful measurements. You'll avoid the inconvenience or expense of buying too much or too little tile and ensure you don't end up buying tiles with a different lot number which may have a slightly different color.

### Step 1

Measure the length and width of the room. If you have not removed baseboards or molding add a half-inch to each measurement. Multiply the length times the width to find the square footage.

### Step 2

Use your tape measure to find the length and width of any adjoining spaces or closets you plan to tile. Don't forget to include the floor spaces in doorways. Multiply the length and width of each area to find the area in square feet.

### Step 3

Add up the square footage of all the areas to be tiled. Since a 12 by12 ceramic tile is one square foot, the number of square feet equals the number of tiles you need to cover the floor space. However, you should allow for cutting tiles to fit or breakage, so add 20 percent to your measurement.

### Step 4

Divide the total number of tiles you need by 12. You should do this because 12 by 12 tiles are usually sold in boxes of 12, so you'll need to know how many boxes of tile to buy. For example, if you calculated a total of 186 square feet, this works out to 15.5 boxes. You will buy full boxes of tiles, so round this up to the next full box. In this example you should buy 16 boxes.