Tile Calculator
Enter your floor's length and width and your tile's length and width to find out exactly how many tiles to buy, plus a waste allowance so you don't run short mid-job.
How this calculation works
The calculator first finds your floor area (length × width) and the area of a single tile (tile length × tile width, converted from centimetres to metres). Dividing floor area by tile area gives the base number of tiles that would exactly cover the floor with zero waste.
Real installs never use every tile whole — cuts at edges, corners, and around fixtures create offcuts, and some tiles crack or are miscut. The waste percentage inflates the base count to cover this, and the result is always rounded up to the next whole tile, because you can't buy a fraction of a tile.
The calculator also shows the theoretical minimum (tiles without waste) alongside the recommended purchase quantity, so you can see exactly how much buffer the waste percentage adds.
Worked example
Recommended waste allowance by layout
How you lay the tile changes how much offcut ends up in the bin. Use this as a starting guide, then round up if the room has many obstacles.
| Layout / situation | Waste allowance | Why |
|---|---|---|
| Simple grid, rectangular room | 10% | Mostly full tiles, few cuts |
| Diagonal or herringbone pattern | 15–20% | Many angled cuts, more offcuts wasted |
| Room with alcoves, islands, or many corners | 15% | More edge cuts needed |
| Large-format tiles (60 cm+) | 10–15% | Each mistake wastes more material |
| First-time DIY installer | 15–20% | Higher chance of miscuts and breakage |
Steps to plan a tiling job
- Measure floor length and width at the widest points and note any alcoves or bump-outs separately.
- Measure the tile itself (not the box label, which can round) in centimetres.
- Choose a waste allowance based on your layout and pattern complexity.
- Buy all tiles in one purchase from the same production batch to avoid shade mismatches.
- Keep a few leftover tiles after installation for future repairs, since tile lines get discontinued.
Common tile sizes and typical uses
| Tile size | Common use |
|---|---|
| 10 × 10 cm | Mosaic accents, small bathroom feature walls |
| 20 × 20 cm | Classic small floor tile, kitchens and bathrooms |
| 30 × 30 cm | Most common general-purpose floor tile |
| 45 × 45 cm / 60 × 60 cm | Modern large-format floors, fewer grout lines |
| 60 × 120 cm and larger | Contemporary minimalist floors and walls |
Tips for buying and laying tile
Always order all boxes for a room in a single purchase and check that every box carries the same dye-lot or batch number printed on the label — shade can vary noticeably between batches even for the identical product code.
Plan the layout before cutting the first tile: dry-fit a row across the room's longest visible wall to decide where cuts fall, so narrow slivers end up in corners or under cabinets rather than along a prominent edge.
Leave expansion gaps at walls (typically 2-3 mm, covered later by trim or baseboard) and keep grout joints consistent, usually 2-5 mm for floor tile, wider for rustic or handmade tile.