Tile Calculator: How Much Tile Do I Need?
Enter the area and the size of the tile, then choose how it is being laid. The layout matters more than most people expect — a diagonal or herringbone pattern cuts a piece off every edge tile, so it needs meaningfully more material than a straight lay.
Area and tile size
Add a separate area for each surface — a floor and its walls are rarely the same tile.
Waste allowances are starting points for each layout, not measurements. A room full of alcoves and thresholds will use more than a plain rectangle, and it is worth keeping a few spare tiles for future repairs from the same dye lot.
How much tile do I need?
Start with the floor or wall area, add a waste allowance for cutting, then convert to pieces using the tile size. Converting to pieces matters because tile is sold by the box and boxes rarely divide neatly into a room.
Buy from one dye lot if you can. Tile colour shifts between production runs, and a box bought six months later to fix a cracked piece will often be visibly different.
How much waste does each layout need?
| Layout | Waste | Why |
|---|---|---|
| Straight lay | 10% | Square or brick-bond tiles running parallel to the walls |
| Diagonal | 15% | Tiles turned 45°, which cuts a triangle off every edge tile |
| Herringbone or complex | 20% | Interlocking patterns, many angles, or a busy room shape |
These are conventions rather than measurements. Adjust the figure if your room is unusually cut up, or unusually simple.
The pattern is what drives the number. A straight lay only cuts tiles along two walls; turn the same tile 45 degrees and every edge tile becomes an offcut, and most of those offcuts are unusable.
Tile size and piece count
A square foot is 144 square inches, so a 12 in tile is one per square foot, a 6 in tile is four, and a 3 × 6 in subway tile is eight. Small tiles mean far more pieces, more grout lines and more cutting time for the same floor.
| Tile size | Tiles per sq ft |
|---|---|
| 3 × 6 in subway | 8 |
| 6 × 6 in | 4 |
| 12 × 12 in | 1 |
| 12 × 24 in plank | 0.5 |
| 24 × 24 in | 0.25 |
How to measure
Tile usually runs under the trim and up to the threshold, so measure the full floor.
A bathroom floor and its shower walls are different areas with possibly different tiles. Areas are summed before rounding.
It varies between products and is what turns square feet into a shopping quantity.
Common mistakes
- Using a straight-lay allowance for a diagonal or herringbone layout.
- Buying the exact square footage with no allowance for cuts.
- Mixing boxes from different dye lots across one floor.
- Forgetting to keep a few spare tiles for future repairs.
Trimming the room afterwards?
Work out the baseboard run once the floor is down.
Open the Baseboard Calculator →