How many tiles do you need?
A tile calculator divides the area you're covering by the area of one tile, rounds up to a whole tile, then adds a wastage allowance for the pieces you'll cut, break or discard. Enter the length and width of the floor or wall, the size of one tile, and a wastage percentage, and you get the tile count to order.
The formula
- Total area = Area length × Area width
- Tile area = Tile length × Tile width
- Tiles required = Total area ÷ Tile area, rounded up
- Recommended quantity = Tiles required × (1 + wastage ÷ 100), rounded up
Both roundings go up, because you can't buy part of a tile. The wastage allowance shown in the results is the difference between the recommended quantity and the tiles required. Area and tile sizes each have their own unit (mm, cm, m, ft or in), so you can enter the room in feet and the tile in inches.
Worked example
A 5 m × 4 m kitchen floor, tiled with 60 × 60 cm porcelain, with the default 10% wastage:
- Total area: 5 × 4 = 20.00 m².
- Tile area: 0.6 × 0.6 = 0.36 m².
- Tiles required: 20 ÷ 0.36 = 55.6, rounded up to 56.
- With wastage: 56 × 1.10 = 61.6, rounded up to 62 tiles, a wastage allowance of 6.
If the tiles come 4 to a box, that's 15.5 boxes, so you'd buy 16.
Tiles per square meter and per 100 ft²
The count depends only on tile area, so the same table works for floors and walls. These figures are before wastage and ignore grout.
| Tile size | Area of one tile | Tiles per m² | Tiles per 100 ft² |
|---|---|---|---|
| 20 × 20 cm | 0.04 m² | 25.0 | 232.3 |
| 30 × 30 cm | 0.09 m² | 11.1 | 103.2 |
| 30 × 60 cm | 0.18 m² | 5.6 | 51.6 |
| 60 × 60 cm | 0.36 m² | 2.8 | 25.8 |
| 60 × 120 cm | 0.72 m² | 1.4 | 12.9 |
| 12 × 12 in | 1 ft² | 10.8 | 100 |
| 12 × 24 in | 2 ft² | 5.4 | 50 |
| 24 × 24 in | 4 ft² | 2.7 | 25 |
Choosing a wastage percentage
The default of 10% suits a straight-lay floor in a reasonably square room. Tile maker Fireclay Tile suggests at least 15 to 20% extra for typical residential projects, and less on very large commercial jobs where offcuts get reused. Increase the allowance when:
- the pattern is diagonal, herringbone or chevron, which produces a cut at every edge
- the room is small or has lots of corners, pipes and door frames
- tiles are large format, where one bad cut wastes a big piece
- you want spares for future repairs from the same batch
Steps to measure for tiling
- Measure the length and width of the floor or wall to the nearest centimeter or half inch.
- For walls, measure only the area you'll tile. Leave out windows, doors and areas behind fitted units.
- Check the actual tile size printed on the box, which can differ slightly from the nominal size in the product name.
- Enter the dimensions and wastage, then round the recommended quantity up to whole boxes.
Limitations
- The count is based on area, not on a tile-by-tile layout. In a narrow strip, a row of cut tiles can use more whole tiles than the area suggests, so treat very small or narrow spaces with a higher wastage figure.
- Grout joints aren't subtracted, which slightly overstates the count.
- Adhesive, grout, trims and spacers aren't estimated.
Related calculators
- Room calculator: floor and wall areas for a whole room in one step.
- Floor concrete calculator: if you're pouring the slab the tiles will go on.
- Plaster calculator: for walls that need rendering before tiling.
- Area converter: switch between m², ft² and other area units.
Last updated