How this tile calculator works
First it converts your room dimensions from feet to square inches (1 square foot = 144 square inches). Then it divides that area by the area of a single tile (tile length × tile width in inches) and applies the waste allowance you choose. If you enter the number of tiles per box, the result is rounded up to whole boxes — which is how tile is actually sold.
Standard practice is a 10% waste allowance for a simple straight layout and 15% for diagonal or herringbone patterns, because every angled cut produces offcuts that cannot be reused. Small tiles (under 6 inches) produce more waste than large format tiles.
Common tile sizes and their area
- 12 × 12 in = 1.00 sq ft per tile
- 18 × 18 in = 2.25 sq ft per tile
- 24 × 24 in = 4.00 sq ft per tile
- 3 × 6 in subway = 0.125 sq ft per tile