Tile Calculator
Tile counts go wrong at the edges and the cuts. This works out the floor area, the area of a single tile, and how many tiles to buy once a waste allowance is added.
| Room length | ft |
| Room width | ft |
| Tile length | in |
| Tile width | in |
| Waste allowance | % |
Result
Your result will appear here.
How it works
The floor area is length times width. Dividing by the area of one tile gives the theoretical minimum, but no tiling job uses exactly that: tiles are cut at walls, some break, and you need spares from the same batch years later. A waste allowance of 10% covers a straightforward room with a few cuts.
Tile sizes are entered in inches because that is how they are sold, even where the room is measured in feet. The calculator converts both dimensions to feet before dividing, so 12-inch tiles come out at exactly one square foot.
Formula
All areas are converted to square feet first.
- Floor area = room length × room width
- Tile area = (tile length ÷ 12) × (tile width ÷ 12)
- Area with waste = floor area × (1 + waste% ÷ 100)
- Tiles = area with waste ÷ tile area, rounded up
- Square metres = square feet × 0.092903
Worked example
A 10 × 10 ft floor is 100 sq ft. With 12 × 12 inch tiles each covering 1 sq ft and a 10% waste allowance you need 110 sq ft of tile, which is 110 tiles.
Assumptions
The room is assumed to be a simple rectangle with no alcoves, and the pattern is a straight lay. Diagonal and herringbone layouts cut more tiles and typically need 15–20% waste. Large-format tiles, narrow plank tiles and rooms with many corners all increase losses. Grout joints are ignored, which slightly overstates coverage and therefore understates the count — another reason to round up.
Reading the result
Order from a single batch and keep every spare. Dye lots vary between production runs, so a box bought six months later can be visibly different under the same light. If the number is close to a whole box, buy the extra box rather than hope: returning one sealed box is easy, matching a discontinued tile is not. Add underlay or adhesive separately — those are sold by area too, but with their own coverage figures.
For general information only. Confirm quantities with your tiler before ordering.
How to use the Tile Calculator
It takes a few seconds, and every figure is calculated in your browser.
- Enter the room length.
- Enter the room width.
- Enter the tile length.
- Enter the tile width.
- Enter the waste allowance.
- Press Calculate — the result appears in the dark panel beside the form.
- Use Copy, CSV, Share or Print under the result if you want to keep it.
Tile Calculator — frequently asked questions
What formula does the Tile Calculator use?
All areas are converted to square feet first. Floor area = room length × room width Tile area = (tile length ÷ 12) × (tile width ÷ 12) Area with waste = floor area × (1 + waste% ÷ 100) Tiles = area with waste ÷ tile area, rounded up Square metres = square feet × 0.092903
How does the Tile Calculator work?
The floor area is length times width. Dividing by the area of one tile gives the theoretical minimum, but no tiling job uses exactly that: tiles are cut at walls, some break, and you need spares from the same batch years later. A waste allowance of 10% covers a straightforward room with a few cuts. Tile sizes are entered in inches because that is how they are sold, even where the room is measured in feet.
What assumptions and limitations should I know about?
The room is assumed to be a simple rectangle with no alcoves, and the pattern is a straight lay. Diagonal and herringbone layouts cut more tiles and typically need 15–20% waste. Large-format tiles, narrow plank tiles and rooms with many corners all increase losses. Grout joints are ignored, which slightly overstates coverage and therefore understates the count — another reason to round up.
Can you walk through a worked example?
A 10 × 10 ft floor is 100 sq ft. With 12 × 12 inch tiles each covering 1 sq ft and a 10% waste allowance you need 110 sq ft of tile, which is 110 tiles.
Last updated 10 November 2026 · Formula, worked example and assumptions are documented above, and every result is calculated in your browser.