Tile calculator
Tiles and boxes for a floor or wall, with grout gaps and cuts allowed for
Type the area to tile and the tile size. The example is a 10 x 8 ft floor in 12 x 12 inch tiles with 1/8 inch grout lines.
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- Area
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- Boxes
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- Tiles before the extra
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- Each tile with its grout gap
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An estimate of quantity from the sizes you typed, not an order list or a price. Buy all tiles from the same batch, and check wet areas and waterproofing with your local code or a qualified person.
How the tiles are counted
Each tile takes up its own size plus one grout gap in each direction. So the number of tiles per square foot or square metre is 1 / ((tile length + gap) x (tile width + gap)). Tiles needed = area x that figure, plus the allowance for cuts and breakage, rounded up to a whole tile.
Why the allowance matters
Tiles at the edges are cut, and the off-cut is often too small to use. Some break. Diagonal and herringbone layouts cut far more tiles than a straight grid. Batches can differ in shade, so many people keep a few spare tiles for future repairs.
Worked example
A floor 10 ft x 8 ft is 80 sq ft. A 12 in tile with a 1/8 in gap takes 12.125 x 12.125 = 147.0 sq in, which is 1.021 sq ft. 80 / 1.021 = 78.4 tiles. Add 10%: 86.2, so 87 tiles. In boxes of 10 that is 9 boxes.
Walls and odd shapes
For a wall, type its width and height. Leave windows and doors in if they are small; take their area off if they are large. For an L-shaped floor, work out the area with the square footage calculator, then type it as a length with a width of 1.
What it does not count
Adhesive, grout, trim and edging are not included: each product gives its own coverage. The calculator cannot judge whether a floor is suitable to tile.
Defaults and where they come from
Every default is only a starting point. Change any box to match what you are buying or building.
| Default | Value | Source |
|---|---|---|
| Allowance for cuts and breakage | 10% straight; 15% diagonal; 20% herringbone (editable) | Common trade practice repeated in tile retailers' and makers' guides. No standards body sets a figure; large or patterned tiles and small rooms need more. |
| Grout gap | 1/8 in (3 mm after conversion) | A common floor joint. Use the gap your tile maker or installer specifies. |
| Conversions | 1 in = 25.4 mm; 1 sq ft = 144 sq in | Exact definitions. |