100 sq ft is a normal bathroom or small kitchen floor. Here is the count for the most common tile, 12 × 12 inches, and then the other sizes in the table.
For 100 sq ft with 12 × 12 tiles: 98 tiles exact, buy 108 tiles with the 10% extra for cuts and breakage. That is 11 boxes of 10 tiles.
Step 1: One tile's area, with the gap tiles sit with a small grout gap (⅛ inch here). (12 + 0.125) × (12 + 0.125) ÷ 144 = 1.0209 sq ft per tile. The math always uses this full number.
Step 2: Exact tiles 100 ÷ 1.0209 = 97.95, rounded UP to whole tiles = 98 tiles. Tiles are only sold whole, so every count rounds up.
Step 3: Add 10% extra, on the whole tiles 98 × 1.1 = 107.8, rounded up again = 108 tiles to buy.
Step 4: Boxes 108 ÷ 10 tiles per box = 10.8, rounded up = 11 boxes.
The same 100 sq ft room, other tile sizes (⅛ inch gap, 10% extra included in "to buy"):
| Tile size | Exact tiles | Tiles to buy | Boxes of 10 |
|---|---|---|---|
| 6 × 6 in | 384 | 423 | 43 |
| 12 × 12 in | 98 | 108 | 11 |
| 18 × 18 in | 44 | 49 | 5 |
| 24 × 24 in | 25 | 28 | 3 |
Edge tiles must be cut, some break, and a few spares save you if a tile cracks years later when that pattern may no longer be sold. Pros order 10% extra as standard, 15% for diagonal patterns.
A little. A bigger gap means each tile covers slightly more, so you need slightly fewer tiles. Our calculator lets you pick the gap, the count updates with it.
Yes, area is area. Measure the wall (length × height), take off nothing for small fittings, and use the same steps.