How to Calculate Floor Tiles

Use the tape measure to measure the length and width of the room to tile.

Multiply the length by the width to find the room's square footage.

Multiply the square footage by 10 percent, or 0.10, to determine the additional amount for mistakes and waste.

Add this number to the square footage measurement for the total area to be covered by tile.

Divide this number by the square footage found on a carton of floor tiles to determine how many cartons of tile are required.