Formula
The tile face is converted from square inches to square feet:
tiles = ceil(area × (1 + waste / 100) / (width × height / 144))
A 12 by 12 inch tile is one square foot. Grout width is not subtracted from the tile.
Assumptions
- Every tile is the same rectangle.
- Waste covers cuts.
- A partial tile is bought whole.
Worked example
120 square feet with 10% waste and 12 inch tiles needs 132 tiles.
Input definitions
- Tile face
- The width and height of one tile, in inches, before grout.
Limitations
Trim pieces, a second tile size, and a pattern that needs more cuts are not counted.
Questions
Why 132 tiles for a 120 square foot room?
Ten percent waste makes 132 square feet, and each 12 inch tile covers one of them.
Does grout reduce the count?
Not here. The joint is small compared with the waste percent, and the tile is still ordered whole.