You've reached a dilemma in your remodeling project: You want to estimate the material costs but can't figure out how to calculate the amount of tile needed for the backsplash. Unlike flooring, which is calculated in square feet or square yards, tiles used for backsplashes are often less than a foot square. Calculating the amount of tile you'll need requires that you first determine the backsplash area and then figure how many tiles you will need for the job.
Things You'll Need
 Tape measure

Find the total backsplash area in square inches. To find this number, multiply the height times the width of each section and add all wall totals together. For our example, we'll use one wall that is 8 feet long by 22 inches high and a second wall that is 6 feet long by 22 inches high. Because we're estimating, we'll always round up to the next whole number:
8 feet X 12 inches = 96 inches. 96 inches X 22 inches = 2112 square inches.
6 feet X 12 inches = 72 inches. 72 inches X 22 inches = 1584 square inches.
2112 + 1584 = 3696 square inches total area to be covered.

Add 7 percent to the total area; this will be your minimum waste allowance:
3696 X 0.07 = 259.
3696 + 259 = 3955 square inches of material needed.

Multiply the length times the width of your chosen backsplash tile. For our example, we'll use a tile that is 8 inches tall/long by 6 inches wide:
8 X 6 = 48 square inches of area per tile.

Divide the area per tile into the total material needed:
3955 divided by 48 equals 83 tiles required for the backsplash.
Tips & Warnings
 Your grout line area will be considered as cutting waste and is not added to the calculation.
 A backsplash with diagonal cuts should have a waste allowance of at least 10 percent.
 Because tiles come in batch and dye lots, you should always purchase extra tiles and store them in a dry area in case you need to replace a tile in the future.
References
 Photo Credit Tim Klein/Stockbyte/Getty Images