What your result means
Tiles needed already includes your waste allowance, and boxes to buy rounds up to whole boxes. The adhesive and grout figures are rules of thumb for a standard notched trowel and typical joint width — thick-bed applications and wide joints use considerably more.
Buy the spare box now, not when a tile cracks
Tile ranges are discontinued constantly, and even a surviving range shifts shade between production batches. A single cracked tile three years later is a trivial repair if you have a match and a full re-tile if you do not.
The same applies to cuts. Keep the usable offcuts from the first fix — they are exactly the pieces you will want for a patch behind a future appliance or fitting.
How it works
The area to tile is divided by the area of a single tile to get the raw count, the waste allowance is added, and the total is rounded up. Box counts round up again because tiles are sold by the box. Adhesive and grout are estimated per square metre.
How to use this calculator
- Enter the dimensions of the area in metres — length × width for a floor, or width × height for a wall.
- Enter the tile size in centimetres.
- Set a waste allowance — 10% for a straight lay, more for diagonal or mosaic work.
- Enter tiles per box from the product listing.
Formula
Tile area in m² = (width cm ÷ 100) × (height cm ÷ 100). Adhesive ≈ 4 kg/m², grout ≈ 1 kg/m² for standard joints.
Example calculation
A 3 × 2.4 m wall with 30 × 60 cm tiles and 10% waste:
7.2 ÷ 0.18 = 40 tiles
With 10% waste = 44 tiles
At 8 per box = 6 boxes (48 tiles)
Frequently asked questions
How much waste should I allow for tiles?＋
Ten percent for a straight lay on a simple rectangle. Fifteen to twenty for diagonal patterns, herringbone, or rooms with many cuts around fittings. Large-format tiles waste more because each cut discards a bigger piece.
Do grout joints change the tile count?＋
Marginally. Joints of 2–3 mm reduce the number of tiles by a fraction of a percent, which the waste allowance more than absorbs. Very wide joints on rustic tiles are worth accounting for manually.
How much adhesive will I really use?＋
Around 4 kg per square metre with a standard notched trowel on a flat surface. Uneven walls, large-format tiles requiring back-buttering, and thick-bed methods can push this above 6 kg.
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Assumptions & limitations
Every figure here comes from a simplified model. Keep these limits in mind when reading your result:
- Assumes a rectangular area — break irregular spaces into rectangles and add them.
- Grout joint width is ignored in the tile count; the waste allowance absorbs it.
- Adhesive and grout figures are typical averages and vary with trowel size, tile format and substrate flatness.
- Excludes trim, edging strips, primer and levelling compound.