Tile calculator
Room area divided by tile area gives the bare count. The cuts at the edges, the breakages and the spares you will want in five years need a waste allowance on top, and tiles are bought by the box.
- Boxes to buy
- 11
- Area to cover, m²
- 14.40
- Tiles with no waste
- 40
- Spare tiles left over
- 4
- Area the boxes cover, m²
- 15.84
- Tiles per m²
- 2.78
- Cost of the boxes
- —
The formula
Tiles = ⌈(room area ÷ tile area) × (1 + waste)⌉. Boxes = ⌈tiles ÷ tiles per box⌉. Tile dimensions are entered in centimetres and converted to metres.
Worked example
A 4.5 × 3.2 m room is 14.4 m². With 60 × 60 cm tiles that is 40 tiles exactly, 44 with a 10% allowance, which is 11 boxes of four — leaving four spares.
How to use it
- 1Use 10% for a straight layout in a regular room, 15% for diagonal or herringbone, and up to 20% for small or awkward rooms.
- 2Buy every box from the same batch number. Shade varies between batches, and a later box will not match.
- 3Keep a few spares after the job. Replacing one cracked tile years later is impossible without them.
Questions people ask
Should I subtract the area under fitted units?
Only where you are certain they will never move. A kitchen or bathroom refit later is far easier on a floor tiled wall to wall.
Does grout width change the count?
Slightly — each joint adds a few millimetres to the effective tile size, so you need marginally fewer. The waste allowance absorbs it, so it is not worth correcting for.
Last reviewed: 2026-10-20