How many tiles do I need
A short guide to why “area ÷ tile area” is not enough and what each number counts.
1. The basic formula
Multiply width × length for the area and divide by one tile’s area; round up. Example (with 0 mm grout and “From the corner” layout): 3.0 × 3.0 m with 60 × 60 cm tiles gives 9 m² ÷ 0.36 m² = 25 tiles, and they fit exactly.
2. Pieces, source tiles and purchase
With 3.2 × 3.0 m and the same tile there are 30 pieces: 25 whole and 5 strips of 20 × 60 cm. Without reusing offcuts you start from 30 tiles. If you reuse offcuts, each 60 cm tile gives two 20 cm strips (with a 2 mm saw cut three do not fit), so the 5 strips come from 3 tiles: 28 source tiles. Add the allowance you choose (10 %: 31).
3. A real source of confusion: 40 and 42
A 2.4 × 3 m bathroom with 30 × 60 cm tiles and 3 mm grout gives 40 pieces starting from the corner (28 whole and 12 cut) and 45 pieces centered. Of those 45, the end strips pair up and the source tiles drop to 42. 40 and 42 are different things: one counts pieces with one start, the other source tiles with another.
4. Grout
Grout separates tiles and changes how many fit per row. With 30 cm tiles and 3 mm grout, 2.0 m fits 6 (6 × 303 mm = 1.818 m) plus a cut piece.
5. Breakage allowance
There is no universal figure: it depends on the tile, the pattern and the installer. Tesela uses 10 % by default and lets you change it. It is your allowance, not a guarantee.