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.
The tile formula, worked through
Tiles needed = (area to cover / area of one tile) x (1 + waste allowance), rounded up to a whole tile. Work in square metres for both areas: a tile measured in centimetres is converted by dividing each side by 100 before multiplying.
For the default floor of 3 m by 2.5 m with 30 x 30 cm tiles, the area is 3 x 2.5 = 7.50 m2 and one tile is 0.3 x 0.3 = 0.09 m2. Dividing gives 83.33 tiles to cover the floor exactly. A 10% waste allowance takes that to 91.67, which rounds up to 92 tiles to buy.
How many tiles per square metre, by tile size
The number of tiles in a square metre is 1 divided by the area of one tile. Smaller tiles need far more pieces for the same floor, which is also more cutting, more grout and more labour. The last column applies the formula above to a 10 m2 area with 10% waste.
| Tile size | Typical use | One tile | Tiles per m2 | For 10 m2 + 10% |
|---|---|---|---|---|
| 10 x 10 cm | Splashbacks, mosaic-style borders | 0.0100 m2 | 100.00 | 1100 |
| 7.5 x 15 cm | Metro (subway) wall tiles | 0.0113 m2 | 88.89 | 978 |
| 10 x 20 cm | Metro wall tiles, larger format | 0.0200 m2 | 50.00 | 550 |
| 15 x 15 cm | Kitchen and bathroom walls | 0.0225 m2 | 44.44 | 489 |
| 20 x 20 cm | Walls and small floors | 0.0400 m2 | 25.00 | 275 |
| 25 x 40 cm | Bathroom walls | 0.1000 m2 | 10.00 | 110 |
| 30 x 30 cm | Floors, the classic size | 0.0900 m2 | 11.11 | 123 |
| 30 x 60 cm | Floors and feature walls | 0.1800 m2 | 5.56 | 62 |
| 45 x 45 cm | Kitchen and hallway floors | 0.2025 m2 | 4.94 | 55 |
| 60 x 60 cm | Large-format floors | 0.3600 m2 | 2.78 | 31 |
| 60 x 120 cm | Large-format floors, open plan | 0.7200 m2 | 1.39 | 16 |
| 20 x 120 cm | Wood-effect planks | 0.2400 m2 | 4.17 | 46 |
Tiles needed by area and tile size
Each cell is the number of tiles to buy for that area, including a 10% waste allowance and rounded up. Use 15% instead for diagonal or herringbone layouts, which the calculator above handles if you change the waste field.
| Area | 10 x 20 cm | 20 x 20 cm | 30 x 30 cm | 30 x 60 cm | 60 x 60 cm |
|---|---|---|---|---|---|
| 2 m2 | 110 | 55 | 25 | 13 | 7 |
| 4 m2 | 220 | 110 | 49 | 25 | 13 |
| 6 m2 | 330 | 165 | 74 | 37 | 19 |
| 8 m2 | 440 | 220 | 98 | 49 | 25 |
| 10 m2 | 550 | 275 | 123 | 62 | 31 |
| 15 m2 | 825 | 413 | 184 | 92 | 46 |
| 20 m2 | 1100 | 550 | 245 | 123 | 62 |
| 30 m2 | 1650 | 825 | 367 | 184 | 92 |
Tiles are usually sold by the box. Divide the count by the tiles per box printed on the packaging and round up again.
How to work out m2 for flooring in an L-shaped room
The calculator takes one length and one width, which is a rectangle. For any other shape, split the floor into rectangles, measure each one to the wall (not the skirting), and add the areas. Enter the total as the length with a width of 1. For an L-shaped kitchen:
| Part | Sum | Area |
|---|---|---|
| Main rectangle | 4.2 m x 3.0 m | 12.60 m2 |
| Leg of the L | 1.8 m x 1.5 m | 2.70 m2 |
| Total floor | 12.60 + 2.70 | 15.30 m2 |
| 30 x 30 cm tiles, no waste | 15.30 / 0.09, rounded up | 170 tiles |
| With 10% waste | 170.00 x 1.1, rounded up | 187 tiles |
Do not subtract fitted units unless you are certain they will never move: tiling under a kitchen run costs a few extra tiles but saves a patch job when the units are replaced. For walls, measure each wall as its own rectangle and subtract doors and windows, as in the bathroom tile guide. If you are painting the walls you are not tiling, the paint calculator works out wall area from the room size and wall height.
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.
How do I work out m2 for flooring?
Measure the length and width of the floor in metres and multiply them: a 4 m by 3 m room is 12 square metres. For an L-shaped room, split the floor into rectangles, work out each one and add them together. A 4.2 m by 3.0 m kitchen with a 1.8 m by 1.5 m leg is 12.6 + 2.7 = 15.3 square metres.
How many tiles are in a square metre?
Divide 1 by the area of one tile in square metres. A 30 x 30 cm tile is 0.09 square metres, so about 11.1 tiles cover a square metre. A 20 x 20 cm tile gives 25 per square metre, a 60 x 60 cm tile about 2.8, and 10 x 10 cm tiles exactly 100, all before waste.
How many 60x60 tiles do I need for 10 m2?
31 tiles with a 10 percent waste allowance. One 60 x 60 cm tile covers 0.36 square metres, so 10 square metres needs 27.8 tiles exactly. Adding 10 percent gives 30.6, which rounds up to 31.
Does the grout gap change how many tiles I need?
Slightly, and in your favour. The calculator uses the tile's face size, so the count is a little generous. A 3 mm joint makes each 30 cm tile cover about 2 percent more area, and each 10 cm tile about 6 percent more, which comes out of your waste allowance rather than adding to it.
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