Plot No. 63 · Home & Garden
Tile Calculator
Work out how many tiles a floor or wall needs. It divides the area in square metres by the area of one tile, then adds a waste allowance for cuts and breakages. The result is the total tile count to buy, rounded up to a whole number.
The tile count already includes your waste allowance and is rounded up to whole tiles. Keep a few spares back after the job for future repairs.
The link saves your inputs so you can bookmark or share this exact result.
How the tile count is worked out
The calculator divides the area you are tiling by the area of a single tile, then adds a waste allowance for cuts and breakages. Area is length times width in square metres. One tile's area is its width times its height, converted from centimetres to metres, so a 30 by 30 cm tile is 0.09 square metres.
Dividing the floor area by the tile area gives the bare number of tiles, and multiplying by one plus the waste percentage covers the off-cuts that never fit anywhere else. The final figure is rounded up, because you cannot buy part of a tile.
How to use the tile calculator
- Enter the length and width of the area in metres.
- Enter the tile width and height in centimetres as printed on the box.
- Set the waste allowance, then read off the total number of tiles to buy.
Worked examples
Small bathroom floor
Inputs: 3 m by 2.5 m area, 30 cm by 30 cm tiles, 10 percent waste
Result: 7.5 square metres needs about 83 tiles bare, and 92 tiles once the 10 percent waste is added and the count is rounded up.
Diagonal layout on the same floor
Inputs: Same area and tile but 15 percent waste for the diagonal cuts
Result: About 96 tiles, the extra few covering the heavier off-cut loss a diagonal pattern creates.
Limitations and common mistakes
Edge cases and limitations
- It assumes one rectangular area. Tile an L-shaped room as two rectangles and add the counts together.
- It does not account for the grout gap, which is usually small enough to ignore but does slightly reduce the tiles needed on big jobs.
- Pattern repeats and feature strips are not modelled, so add extra by hand for those.
Common mistakes
- Mixing units by entering the tile size in metres instead of centimetres, which throws the count out wildly.
- Skipping the waste allowance, then running short when a few tiles crack during cutting near the end of the job.
Frequently asked questions
How many tiles do I need?
Divide the area by one tile's area, then add waste. A 3 m by 2.5 m floor is 7.5 square metres. With 30 cm tiles (0.09 square metres each) and 10 percent waste, that is about 92 tiles.
How much waste should I allow for tiles?
Ten percent is the standard allowance for straight layouts. Use 15 percent for diagonal or herringbone patterns, and a touch more for rooms with lots of awkward cuts, because off-cuts rarely fit elsewhere.
Should I buy all the tiles from one batch?
Yes. Tile colour can shift slightly between production batches, so order the full count at once and check the batch number on every box. Keeping a few spares after the job protects you against future breakages.
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