CostBuildrTile Calculators
Tiles are sold by the box, but your floor and walls are measured in square feet or meters — and the mismatch between the two is where costly errors happen. Under-ordering means a second batch that may not match the shade of the first, while over-ordering wastes money on boxes you cannot return once opened. This calculator bridges the gap by converting your room dimensions into precise tile and box counts, with a configurable wastage allowance built in.
Common questions
How much wastage should I add when ordering tiles?
For a straightforward rectangular room with minimal cuts, add 5–7 % for wastage. If the room has many corners, curves, or you are laying tiles diagonally, increase the allowance to 10–15 %. Larger format tiles (600 × 600 mm and above) tend to produce bigger offcuts that cannot be reused, so lean toward the higher end. Always round up to the next full box — you cannot buy half a box, and having a few spares is useful for future repairs.
How do I figure out how many tiles come in a box?
The box label lists the number of pieces and total coverage area (e.g., '4 tiles, 1.44 m²' for 600 × 600 mm tiles). If you only know the tile size, divide the box coverage area by the area of one tile to get the count. Common examples: 300 × 300 mm tiles typically come 10–12 per box (~1 m²), 600 × 600 mm tiles come 4 per box (~1.44 m²), and 600 × 1200 mm tiles come 2 per box (~1.44 m²). These vary by manufacturer, so confirm with your supplier.
Do I need to account for grout lines in my tile calculation?
For practical estimation purposes, the grout joint (usually 1.5–3 mm for rectified tiles, 3–5 mm for non-rectified) has a negligible effect on the total tile count. On a 10 m² floor with 3 mm joints between 600 × 600 mm tiles, the grout lines reduce the net tile area by less than 1 %, which is already covered by your wastage allowance. Where grout joints matter more is in material cost for grout powder itself — about 0.5 kg of grout per square meter for standard joints.
Is there a difference in calculation for floor tiles vs wall tiles?
The math is the same — area of the surface divided by the area of one tile — but the inputs differ. For floors, you measure length × width. For walls, you measure length × height for each wall, then subtract the area of doors, windows, and any other openings. Wall tiling also tends to have more cuts around fixtures (taps, switches, niches), so it is wise to add a higher wastage percentage (8–12 %) compared to a simple floor layout.