Tile Calculator – How Many Tiles Do You Need?
Calculate the exact number of tiles needed for floor or wall projects.
Tile Coverage and Waste Factors
Calculating tile quantities requires the room's square footage plus a waste allowance for cuts, breakage, and future repairs. The required waste factor depends on tile size, room complexity, and layout pattern.
| Layout Pattern | Waste Factor | Reason |
|---|---|---|
| Straight lay (grid) | 10% | Minimal cuts at room edges |
| Diagonal (45°) | 15–20% | More edge cuts required |
| Herringbone | 15–20% | Complex angle cuts |
| Large format tiles | 15% | One break = larger loss |
| Small mosaic tiles | 5–10% | Sheets absorb edge cuts |
Common tile sizes: 12×12 in (standard), 18×18 in (modern residential), 24×24 in (large format), 4×16 in (subway tile). Grout joint width affects the number of tiles needed — wider joints (3/8 in) slightly reduce tile count versus tight-set (1/16 in). For floor tiles, add a setting bed of thinset mortar: one 50 lb bag covers approximately 40–50 sq ft.
How many tiles do I need for 100 sq ft?
For 12×12 inch tiles: 100 tiles + 10% waste = 110 tiles. For 18×18 inch tiles: ~45 tiles + 15% waste = ~52 tiles.
Do I need extra tiles for future repairs?
Yes — always save 5–10% extra from the same batch/dye lot. Tile colors shift between production runs, making exact matches impossible later.