Calcylator
Tile Quantity

How many tiles do I need:
area ÷ tile area, plus waste

Turn tile dimensions into square metres, add an allowance for cuts, and round up to whole tiles before you order.

Calcylator Editorial Team

Updated · 6 min read

How many tiles do I need?

Divide the surface area, plus a waste allowance, by the area of one tile, and round up to a whole tile. A 14.7 m² floor with 600 × 600 mm tiles and 10% waste needs 45 tiles.

The tile quantity calculator asks for the surface area in square metres, the area of a single tile in square metres, and a waste percentage from 0 to 30 (default 10). It rounds up, because you cannot buy part of a tile.

Tile quantity formula and example

Number of tiles =tiles = ceil(area × (1 + waste ÷ 100) ÷ tile area)
area:
surface to cover, in m²
tile area:
length × width of one tile, in m²
waste:
allowance for cuts and breakage, in percent
ceil:
round up to the next whole tile

  • Floor area

    14.7 m²

  • Tile size

    600 × 600 mm = 0.36 m²

  • Waste

    10%

  • Area with waste

    14.7 × 1.10 = 16.17 m²

Tiles required

45

16.17 ÷ 0.36 = 44.92, which rounds up to 45 tiles.

  1. Work out the surface area in square metres.
  2. Convert the tile size to metres and multiply for one tile's area.
  3. Choose a waste allowance.
  4. Divide, then round up to the next whole tile.

How waste changes the count

14.7 m² floor with 600 × 600 mm tiles
WasteTiles required
0%41
10%45
15%47

The zero waste figure of 41 would only work if every tile were used whole with no breakage, which almost never happens. Plan for at least the default allowance, and more for diagonal layouts, many small cuts or patterned tiles that need matching.

Small tiles, boxes and a second example

Before you order, plan the layout. Starting from the centre of the room rather than a corner usually leaves cuts of similar width on both sides of the floor, instead of one full-width row on one side and a thin sliver on the other. Slivers waste tiles and look untidy, so a quick sketch before ordering can change the final count.

A handy shortcut is tiles per square metre. A 0.36 m² tile means 1 ÷ 0.36 = 2.78 tiles for every square metre, and a 0.09 m² tile means 11.11 per square metre. Multiply that by the area, add waste, and you have the same answer by a different route.

Small tiles show the same method. A splashback of 5.2 m² in 300 × 300 mm tiles has a tile area of 0.09 m². With 10% waste, that is 5.72 m² divided by 0.09, which is 63.56, so you need 64 tiles.

Tiles are sold in boxes, each covering a stated area. After the calculator gives the number of tiles, divide by the tiles per box and round up again. Buying all the boxes in one go also keeps shades consistent, as colour can differ between production batches.

Common mistakes when counting tiles

  • Typing the tile size in millimetres. The calculator expects square metres, so 600 × 600 mm must be entered as 0.36.
  • Forgetting grout joints. For small tiles the joint is a noticeable share of the area, so ask the tile supplier for the stated coverage.
  • Dividing the area by the tile area without the waste allowance, then running short on the last row.
  • Not rounding up. 44.92 tiles means 45, never 44.

Common questions

How many tiles do I need for a room?

Divide the room area plus about 10% waste by the area of one tile and round up. A 14.7 m² floor with 600 × 600 mm tiles needs 14.7 × 1.10 ÷ 0.36 = 44.9, so order 45 tiles.

How much extra should I buy when tiling?

Ten percent is a common allowance and the calculator's default. Diagonal layouts, many cuts or patterned tiles may need 15 percent or more. Keep a few spare tiles afterwards for future repairs.

How do I find the area of one tile?

Multiply its length by its width, both in metres. A 600 × 600 mm tile is 0.6 m × 0.6 m = 0.36 m². A 300 × 300 mm tile is 0.09 m². Always convert millimetres to metres first.

Why does the tile calculator round up?

Tiles are sold whole, so any fraction means you need one more. The calculation 44.92 tiles becomes 45. Rounding down would leave you short, and a later order may not match the original batch.

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