How the tile calculator works
It works out the area in square feet, converts it to square inches and divides by the area of one tile. Then it adds the extra percentage for cuts and breakage and rounds up to whole tiles. If you enter how many tiles come in a box, it also rounds up to whole boxes. Grout lines are ignored, which leaves you very slightly over rather than short.
Tiles per square foot
| Tile size | Tiles per ft² |
|---|---|
| 4 × 4 in | 9 |
| 6 × 6 in | 4 |
| 12 × 12 in | 1 |
| 12 × 24 in | 0.5 |
| 24 × 24 in | 0.25 |
How much extra tile to buy
Add about 10% for a straight layout in a simple room, and 15% or more for diagonal and herringbone patterns, rooms with many corners, or large tiles that leave big offcuts. Keep a few spare tiles after the job: matching the colour batch years later can be hard.
Frequently asked questions
How many tiles do I need for 100 square feet?
With 12 × 12 inch tiles, 100 tiles plus about 10 percent extra, so 110. With 6 × 6 inch tiles, 400 plus extra, so 440.
How do I measure an L-shaped room?
Split it into two rectangles, work each one out, and add the tile counts together.
Should I subtract the area under cabinets?
Yes, if the tile will not run under them. Measure only the area that will be tiled.