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Tile Calculator
How many tiles and boxes for a floor or wall, with grout gap and waste.
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The area to tile
The tiles
Keep a few spare tiles from the same batch after the job: shades vary between production runs, and a matching tile for a later repair can be hard to find. Tiles per box is printed on the box or the product page.
How to use it
- Pick Metric or Imperial.
- Enter the floor or wall size, or the area if you already know it, and any area to leave out.
- Enter the tile size, the grout gap and a waste allowance.
- Add the number of tiles per box to see how many boxes to buy.
Questions
How is the number of tiles worked out?
Each tile covers its own size plus one grout gap in each direction. The area to tile is divided by that, then the waste allowance is added and the result rounded up to whole tiles. A 30 x 30 cm tile with a 3 mm gap covers 30.3 x 30.3 cm.
How much waste should I allow?
Around 10 percent is a common allowance for a straight lay in an ordinary room. Diagonal and herringbone patterns cut more tiles, so 15 percent or more is usual. Rooms with lots of corners, pipes and cut-outs, or very large tiles, can need more again.
Should I subtract doors and windows?
For walls, yes: subtract a window, a bath or a fitted unit that will not be tiled behind. Small cut-outs are better left in, because the tiles around them still have to be cut and the offcuts are rarely reusable.
Does it work for walls?
Yes. Enter the wall's width and height as the length and width. For several walls, add their areas together and use the area tab, or work out each wall and add the tile counts.
About this tool
About the tile calculator
Running out of tiles halfway through a job is a problem, because a later batch can differ slightly in shade. This calculator tells you how many to buy, including the extra you need for cuts and breakages.
What you enter
- The area: length and width, or a known area, minus anything that will not be tiled, such as a bath or a window.
- The tile size and the grout gap between tiles.
- A waste allowance: about 10 percent for a straight lay is typical, 15 percent for diagonal or herringbone patterns, more for rooms with many cuts.
- Tiles per box, if you want the number of boxes.
How it counts
Each tile covers its own size plus one grout gap in each direction. The area is divided by that, the waste allowance is added, and the result is rounded up to whole tiles and then to whole boxes, with the area those boxes cover.
It works for walls too: enter a wall's width and height as the length and width. Keep a few spare tiles from the same batch for future repairs. Switch between metric and imperial at any time.
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