Short answer: with the most common 12×12 inch tiles, a 100 sq ft floor needs 100 tiles before waste — buy 110 to cover cuts and breakage. Bigger tiles mean fewer pieces; smaller tiles mean many more.
Tile count for 100 sq ft by tile size
| Tile size | Tiles to buy (incl. 10% waste) |
|---|---|
| 6×6 inches | 440 tiles |
| 12×12 inches | 110 tiles |
| 12×24 inches | 55 tiles |
| 18×18 inches | 49 tiles |
| 24×24 inches | 28 tiles |
The math is simple: divide 100 sq ft by the area of one tile, then add 10%. A 12×24 tile covers 2 sq ft, so 50 tiles cover the floor — 55 with waste. An 18×18 tile covers 2.25 sq ft, so the count drops to 49.
How many boxes is that?
Tiles are sold by the box, and boxes are labeled by coverage, not count — a typical box covers 10–15 sq ft. For 100 sq ft plus waste, plan on roughly 8–11 boxes depending on the brand. Always buy every box from the same batch: shade varies slightly between production runs, and a mismatched patch in the middle of the floor is forever.
When to add more than 10% waste
Raise the allowance to 15% for diagonal (diamond) layouts, large-format tiles over 15 inches, mosaic sheets, and rooms with lots of corners, alcoves or curved cuts. Pros also keep a few leftover tiles from the original batch for future repairs — replacements bought years later rarely match.
Tiling a different area or an unusual tile size? Get the exact count in our tile calculator.