Tiles & flooring· 2 min read
How Much Extra Tile to Buy: Straight, Offset and Diagonal
A 4 × 3 m room with 60 × 30 cm tiles: how many tiles a straight, offset or diagonal layout needs, and why area alone is not enough.
A 4 × 3 m floor is 12 m². A 60 × 30 cm tile (about 24 × 12 in) with a 3 mm joint covers roughly 0.18 m². “Area divided by tile” gives 66 tiles. You will need more — exactly how many depends on the pattern and where you start.
Patterns compared
| Layout | Whole | Cut | Total | +10 % reserve |
|---|---|---|---|---|
| Straight, from a corner | 54 | 16 | 70 | 77 |
| Straight, from the centre | 45 | 32 | 77 | 85 |
| Half offset, from the centre | 50 | 32 | 82 | 91 |
| Third offset, from the centre | 51 | 33 | 84 | 93 |
| Diagonal 45°, from the centre | 41 | 48 | 89 | 98 |
Every cut tile is a whole tile bought — tile offcuts are rarely reusable. That is why the layout count is always higher than the area estimate.
Corner or centre?
Starting from a corner needs the fewest tiles, but opposite walls end up with different strips — here 273 mm on one side and full tiles on the other. Starting from the centre gives equal strips on both sides (135 mm), which looks far better, for 7 more tiles.
Watch the one-third offset: with this tile it leaves a strip only 89 mm wide. Narrow pieces are hard to cut and crack easily. The calculator warns you about very thin strips.
How much reserve
- The reserve covers broken tiles, bad cuts and future repairs.
- Around 10 % is common for straight layouts; diagonal and herringbone layouts need 15–20 % or more. Large formats and small or irregular rooms need even more — ask your supplier.
- Keep at least one box from the same batch — shade and size vary between batches, and a later order may not match.