Tile quantities
Boxes of tiles to buy and cost
- where
- boxes to buy
- area to tile (m²)
- waste allowance (%)
- coverage per box (m²)
- area bought (m²)
- price per box (£)
Explain this equation
Converts the area to tile into whole boxes to buy, the area you will actually get, and the cost.
A is the area, w the waste allowance and Cb the area one box covers as printed on the box. B is the number of boxes, Ab the area those boxes cover and P the price per box.
Adding waste then dividing by the box coverage gives the boxes needed; rounding up to a whole box gives what you buy. The bought area is simply boxes times coverage, and the cost is boxes times price.
Sense check: 12.4 m² plus 10% is 13.6 m²; at 1.44 m² per box that is 9.5, so 10 boxes covering 14.4 m².
Watch out: box coverage normally ignores the joint, so it is slightly on the safe side. Check every box has the same batch code.
Whole boxes needed to cover the area plus waste, the area you will actually buy and the cost.
Enter your values to see the result.
Good to know
Box coverage is usually the tile face area times the tiles in the box, with no joint added, so it slightly understates true coverage and errs on the safe side. Check all boxes carry the same batch (shade) code. Use the tile count calculator for the waste figure that suits your layout.
Common mistake
Rounding the area to the nearest box before adding waste, then finding the job is a box short on the last row.
Limits
Assumes every box covers the stated area. Mixed-size or modular packs (e.g. Versailles/opus patterns) should be calculated from the supplier’s per-pack coverage.
Sources
Results are calculations from the published methods and manufacturer figures shown, and depend on the data you enter. Always follow the tile, adhesive and grout manufacturers’ instructions, BS 5385 and the Tile Association guidance. Coverage rates vary by product and substrate. Check prices and VAT rules with your own records and HMRC.