How to Calculate Tile Requirements

Measure the area

For a floor, measure length and width at the widest points and multiply. A bathroom floor 2.4 m × 1.8 m is 4.32 m². For walls, measure the length and the height of each wall being tiled.

Divide by the tile size

Australian tiles are specified in millimetres — 600 × 600, 300 × 600, 200 × 200 and so on. Convert to metres (600 mm = 0.6 m), multiply for one tile's area, then divide the job area by it.

The 4.32 m² bathroom with 600 × 600 mm tiles: one tile is 0.36 m², so 4.32 ÷ 0.36 = exactly 12 tiles.

Add waste for cuts and breakages

Tiles crack when cut and rooms have corners. Straight lays in simple rooms: 10%. Diagonal, herringbone or brick-bond patterns, or many alcoves: 15%. The 12-tile bathroom becomes 12 × 1.1 = 13.2 → 14 tiles.

Always round up — tiles are indivisible, and one short means a second trip and a possibly different batch.

Batch, shade and calibre

Tiles vary slightly between production runs. The shade (colour tone) and calibre (size) codes are printed on every box — buy all your tiles from matching codes, and check them before the tiler starts. Keep two or three full tiles after the job for future repairs.

Don't forget adhesive and grout

Adhesive and grout are calculated separately by weight and joint width. As a sense-check, a 20 kg bag of adhesive covers roughly 5–8 m² depending on trowel size, and grout consumption depends on tile size and joint spacing. Ask your tiler or tile shop to confirm quantities for your specific product.