How many tiles do I need?
Each tile covers its own size plus one grout joint. Divide the area by that and add extra for cuts and breakage.
Tiles per sq ft = 144 ÷ ((tile length + joint) × (tile width + joint))
Tiles = area × tiles per sq ft × (1 + extra %), rounded up
Tiles = area × tiles per sq ft × (1 + extra %), rounded up
Worked example
A 12 × 10 ft floor is 120 sq ft. 12 × 12 in tiles with ⅛ in joints cover 12.125 × 12.125 = 147 square inches each, so 144 ÷ 147 = 0.979 tiles per sq ft and 117.5 tiles. With 10% extra, buy 130 tiles; in boxes of 10, that's 13 boxes.
Tiles per square foot
| Tile size | Tiles per sq ft (no joint) |
|---|---|
| 3 × 6 in subway | 8 |
| 4 × 4 in | 9 |
| 6 × 24 in plank | 1 |
| 12 × 12 in | 1 |
| 12 × 24 in | 0.5 |
| 24 × 24 in | 0.25 |
Grout joints make each tile cover a little more, so you need slightly fewer than the table shows.
How much extra to buy
About 5 to 10% for straight layouts, 10 to 15% for diagonal or patterned layouts. Keep a few spare tiles: the same color batch can be hard to find later if one cracks.
Limitations
- Odd-shaped rooms: split the room into rectangles, add the areas and use "Square feet".
- Walls: subtract windows, doors and areas behind cabinets from the wall area.
- Large tiles waste more at the edges of small rooms; use the top of the extra range.