Wastage accounts for cuts, breakages, and future replacements. 10% is standard; allow 15–20% for diagonal patterns or complex cuts.
This calculator divides the area you're tiling by the area of a single tile, then adds your chosen wastage percentage to account for cuts, breakages, and future replacements. Enter your room dimensions or the area directly, pick a tile size, and adjust wastage to match your layout.
A straightforward grid layout typically wastes around 10% of tiles to cuts, breakages, and offcuts too small to reuse elsewhere. Diagonal, herringbone, or other patterns that involve more angled cuts waste more material — 15–20% is a safer allowance in those cases. It's always worth ordering slightly more than the bare minimum, since matching a discontinued batch or dye lot later can be difficult or impossible.
300×300mm and 300×600mm are common wall tile sizes; 600×600mm and 600×300mm are more typical for floors, since fewer, larger tiles mean fewer grout lines and a faster lay. If your tiles don't match one of the standard presets, choose Custom and enter the exact width and height in millimetres from the tile's own packaging.
Tile boxes usually list a tile count or coverage area on the packaging. Enter the number of tiles per box and the calculator rounds up to a whole number of boxes — rounding down would leave you short mid-job, so the figure shown is always the minimum number of boxes to buy, not an average.
The same area-and-wastage calculation works for tiling a floor or a wall — the main difference is the tile size you'd typically pick (see above) and, for floors, a slightly higher wastage allowance in rooms with lots of cuts around fixtures like a toilet base or shower tray.