Tile Calculator — How Many Tiles Do You Need?
For 100 square feet of 12×12 in tile you need 100 tiles plus waste — about 110 tiles at a 10% allowance. A 12×12 tile covers exactly 1 square foot; add 10% waste for a straight layout and 15% for diagonal or patterned installs.
Enter the area you are tiling and the size of a single tile. This calculator works out how many tiles you need including cutting waste, and how many boxes to buy.
How to use this calculator
- Measure the length and width of the area you are tiling, in feet.
- Enter the size of one tile in inches (e.g. 12 × 12, or 12 × 24).
- Pick a waste allowance: 10% for a straight lay, 15% for diagonal or patterned layouts.
- Optionally enter the tiles-per-box figure from the product page to get a box count.
The formula
We compare the area you are covering with the area of a single tile, then add waste for cuts and breakage.
Tile area (sq ft) = tile width (in) × tile length (in) ÷ 144 (there are 144 square inches in a square foot).
Tiles = area to cover × (1 + waste %) ÷ tile area, rounded up.
Boxes = tiles ÷ tiles per box, rounded up.
Worked example
A 10 ft × 8 ft floor with 12 in × 12 in tiles, 10% waste.
Area = 10 × 8 = 80 sq ftTile area = 12 × 12 ÷ 144 = 1 sq ftWith waste = 80 × 1.10 = 88 sq ftTiles = 88 ÷ 1 = 88 tiles
You need 88 tiles (12×12) to cover an 80 sq ft floor with 10% waste.
Reference tables
| Tile size | Tile area | Tiles per 100 sq ft |
|---|---|---|
| 6 × 6 in | 0.25 sq ft | 440 |
| 12 × 12 in | 1.0 sq ft | 110 |
| 12 × 24 in | 2.0 sq ft | 55 |
| 18 × 18 in | 2.25 sq ft | 49 |
| 24 × 24 in | 4.0 sq ft | 28 |
Frequently asked questions
How much extra tile should I buy for waste?
Add 10% for a standard straight layout, and 15% for diagonal or patterned installs. Buying from the same batch now avoids shade differences if you need spares later.
How many 12x12 tiles do I need for 100 square feet?
A 12×12 tile covers exactly 1 sq ft, so 100 sq ft needs 100 tiles, plus waste — about 110 tiles at a 10% allowance.
How do I calculate tiles for a wall?
Use the same method with the wall height and width. Subtract large openings like windows, and keep the 10–15% waste allowance for cuts around fixtures.
Why does tile size affect the count but not much the area?
The area you cover is fixed, but smaller tiles mean more cuts at the edges, so percentage waste produces more leftover pieces. Larger tiles waste fewer pieces but each cut costs more.