How to calculate how many tiles you need
Divide the area you're covering by the area of one tile, then add waste: Tiles = (Floor area × (1 + waste%)) ÷ tile area. Keep units consistent — a 60 × 60 cm tile covers 0.36 m², so a 12 m² floor needs 12 ÷ 0.36 ≈ 34 tiles before waste, ~37 with 10%.
Why you need a waste allowance
You can't lay whole tiles everywhere — edges and corners need cuts, some tiles break, and layouts like diagonal or herringbone waste more. 10% is standard for a simple straight layout; use 12–15% for diagonal, patterned, or small rooms with lots of cuts. Keeping a few spares also means a perfect match if one cracks years later.
How many tiles per square metre or 100 sq ft
Tiles needed for common sizes. The last column adds the standard 10% overage and rounds up, exactly as the calculator does. Grout joints are ignored — they make little difference to the count.
| Tile size | Tiles / m² | For 10 m² +10% |
|---|---|---|
| 20 × 20 cm | 25 | 275 |
| 30 × 30 cm | 11.11 | 123 |
| 30 × 60 cm | 5.56 | 62 |
| 40 × 40 cm | 6.25 | 69 |
| 45 × 45 cm | 4.94 | 55 |
| 60 × 60 cm | 2.78 | 31 |
| 60 × 120 cm | 1.39 | 16 |
| 80 × 80 cm | 1.56 | 18 |
| 15 × 90 cm | 7.41 | 82 |
| 20 × 120 cm | 4.17 | 46 |
| Tile size | Tiles / 100 ft² | For 100 ft² +10% |
|---|---|---|
| 12 × 12 in | 100 | 111 |
| 12 × 24 in | 50 | 56 |
| 18 × 18 in | 44.4 | 49 |
| 24 × 24 in | 25 | 28 |
| 6 × 24 in | 100 | 111 |
| 6 × 36 in | 66.7 | 74 |
| 8 × 48 in | 37.5 | 42 |
What overage percentage to use for tile
Overage covers cuts, breakages and spares for future repairs. More cuts means more waste, so the right figure depends mostly on the layout:
| Layout | Typical overage |
|---|---|
| Straight grid, simple square room | 10% |
| Brick / offset pattern | 10–12% |
| Room with many corners, cut-outs or fixtures | 12–15% |
| Diagonal layout | 15% |
| Herringbone or chevron | 15–20% |
Whatever the layout, keep at least one spare box after the job. Tiles from a later batch can differ slightly in colour, so matching a broken tile years later is much easier with leftovers from the original order.
Works for planks and flooring too
Enter your plank or laminate dimensions in place of the tile size and it works the same way. Since flooring is sold by the box, the calculator rounds up to whole boxes and shows the cost.
What overage percentage should I use for tile?
10% for a straight layout in a simple room, around 15% for diagonal, and 15–20% for herringbone or chevron. Add a little more for rooms with lots of corners or cut-outs.
How many 24 × 24 tiles do I need for 100 square feet?
Each 24 × 24 in tile covers 4 sq ft, so 100 sq ft needs 25 tiles — 28 with 10% overage.
How many 60 × 60 tiles are in a square metre?
About 2.78 tiles per m² (each covers 0.36 m²). For 10 m² with 10% overage you need 31 tiles.
How many boxes of tile do I need?
Work out the total tiles including overage, then divide by the tiles per box and round up. 31 tiles at 4 per box is 7.75, so buy 8 boxes. The calculator does this for you once you enter the box size.
Should I buy by tile or box?
Tiles are usually sold by the box. The calculator rounds up to whole boxes so you buy enough — and it's worth having a spare box for repairs.
How much waste for a diagonal pattern?
Bump the waste slider to about 15%. Diagonal and herringbone layouts create far more cut pieces than a straight grid.
Do I subtract for cabinets or fixtures?
For a rough estimate, no — the waste allowance usually covers it. For large built-ins, reduce your area by their footprint first.