How the tile calculator works
Each tile covers its own length × width. The calculator divides the tiled area by the area of one tile, adds your waste allowance for cuts and breakage, and rounds up to whole tiles.
The breakdown shows tiles for the area, the allowance, and the rounding. The scale drawing shows how many tiles fit per row and how many rows, so you can see the cut pieces along the edges.
Formula and assumptions
- L, W
- area to tile, in feet
- waste
- allowance for cuts, pattern, and breakage
Assumptions and limits
- Grout joints are not subtracted, which is slightly conservative.
- Divide the tile count by tiles per box for cartons.
Worked example
An 8 × 6 ft floor, 12 × 12 in tiles, and a 10% allowance.
- Area = 48 sq ft; each tile = 1 sq ft.
- 48 × 1.10 = 52.8 tiles.
- Round up: buy 53 tiles.
These are the calculator’s default values, so the live result above matches this example until you change an input.
How to measure correctly
- Measure the area you will tile, not the room, if the tile stops at a vanity or tub.
- Use the actual tile size from the box, not the nominal name.
- For walls, subtract only large openings such as windows; small cutouts still consume tiles.
Tiles per square foot
| Tile size | Area per tile | Tiles per sq ft | Tiles for 100 sq ft + 10% |
|---|---|---|---|
| 1 × 1 in | 0.007 sq ft | 144 | 15840 |
| 2 × 2 in | 0.028 sq ft | 36 | 3960 |
| 3 × 6 in | 0.125 sq ft | 8 | 880 |
| 4 × 4 in | 0.111 sq ft | 9 | 990 |
| 6 × 6 in | 0.25 sq ft | 4 | 440 |
| 6 × 24 in | 1 sq ft | 1 | 110 |
| 8 × 8 in | 0.444 sq ft | 2.25 | 248 |
| 12 × 12 in | 1 sq ft | 1 | 110 |
| 12 × 24 in | 2 sq ft | 0.50 | 55 |
| 18 × 18 in | 2.25 sq ft | 0.44 | 49 |
| 24 × 24 in | 4 sq ft | 0.25 | 28 |
Tile Calculator FAQ
How do I calculate how many tiles I need?
Divide the area by the area of one tile, add waste, and round up. In feet and inches: tiles = area (sq ft) × 144 ÷ (tile length in × tile width in) × (1 + waste).
How much extra tile should I buy?
Plan more for diagonal, herringbone, and other patterned layouts, small rooms with many cuts, and large-format tile where one broken piece is costly. Use the installer’s or manufacturer’s recommendation.
How many 12×24 tiles do I need for 100 square feet?
Each 12 × 24 in tile is 2 sq ft, so 100 sq ft needs 50 tiles before waste, or 55 with a 10% allowance.
Do grout lines change the tile count?
Slightly, by making each tile cover a little more. Ignoring them is a small, safe overestimate.
How many boxes of tile do I need?
Divide the tile count by tiles per box, or the area by square feet per box, and round up. The tile cost calculator works in boxes.
Should I keep spare tiles?
Yes. Keeping a few from the same lot makes it much easier to replace a cracked tile later.