CalcCoverageHow many tiles do I need?
Tile math is area ÷ tile area — with one honest complication: not every tile you buy ends up whole on the floor. Cuts at edges, breakages, and pattern matching all consume tiles, which is why the trade adds a waste allowance before counting boxes.
Tiles = area (with waste) ÷ tile area · Boxes = area (with waste) ÷ coverage per box
Example: a 10 × 10 ft bathroom floor with 12 × 12 in tiles: 100 sq ft = 100 tiles exactly; with 10% waste, 110 tiles, and at 10 sq ft per box, 11 boxes.
How much waste should I allow?
| Layout | Waste to allow |
|---|---|
| Straight grid, square room | 10% |
| Diagonal (45°) layout | 15% |
| Herringbone / patterned | 15–20% |
| First tiling job, brittle stone | 15% and keep the spares |
Boxes matter more than single tiles for one unglamorous reason: dye lots. Tiles from the same production run match; a box bought six months later may not. Buy the full count — including waste — in one order, and keep the leftovers for future repairs.