Buy more tile than your bare square footage. Add 10% for a straight grid, 15% for a diagonal or running-bond (offset) pattern, and up to 20% for herringbone and other complex layouts. That extra is your waste factor, and skipping it is the single most common tiling mistake.
The cuts at walls, the tiles you crack on the wet saw, and the inevitable breakage during install all eat into your count. Run your room through the tile calculator first so you order close to the right amount in one trip instead of two.
Why waste happens
A tiled floor is never a clean multiple of full tiles. Walls aren't square, rooms aren't sized to your tile, and every perimeter tile gets cut. Those cut-offs are usually too small to reuse, so the material is genuinely lost.
Three things drive your waste up:
- Cuts at every edge. The more perimeter your room has relative to its area, the more cutting you do. Long, narrow rooms and rooms with lots of jogs waste more than a simple square.
- The pattern. Angled and interlocking layouts force more cuts, and those cuts land at awkward angles that can't be reused elsewhere.
- Breakage. Tiles chip on the saw, snap when you handle them, and crack if you set them on an uneven bed. Pros budget for it; so should you.
The numbers by layout
Match your overage to your pattern:
- Straight grid (square or stacked): add 10%. Cuts are simple and predictable, mostly straight runs along the walls.
- Diagonal or running bond (offset/brick): add 15%. Diagonal sends every perimeter tile through the saw at 45 degrees, and an offset pattern leaves staggered partial tiles down each edge.
- Herringbone and complex mosaics: add up to 20%. Interlocking angles mean nearly every edge piece is a custom cut, and many cut-offs are unusable.
If you've never tiled before, round up rather than down. The cost of a few extra tiles is trivial next to the cost of stopping mid-job. For a deeper look at how each layout behaves, see tile layout patterns.
Buy it all in one dye lot
This is the rule people learn the hard way. Tile is dyed in batches, and different dye lots can be visibly different shades — sometimes subtly, sometimes obviously, especially under bright light. The lot number is printed on the box.
Because of this, buy your entire waste-adjusted quantity at once, in a single dye lot. If you under-order and go back for one more box next month, it may not match — and a slightly-off tile in the middle of a floor is hard to hide. The 10-to-20% overage isn't just for cuts; it's your insurance that every tile on the job came from the same batch.
Measure twice. Buy once.
Keep your leftovers
Don't return the unused tiles, and don't toss them. A few spares from the original dye lot are worth keeping for the life of the floor. If a tile ever cracks — a dropped pan, a settling subfloor — you can swap in an exact match instead of patching with a near-miss.
Label the box with the room and date, and store it somewhere dry. Future you will be grateful.
Tools that reduce waste
You can't eliminate waste, but clean cutting keeps it close to the minimum:
- A manual tile cutter scores and snaps straight lines fast and chip-free, ideal for grid and subway layouts where most cuts are straight.
- For diagonal and herringbone work, a wet saw handles the angles and curved cuts a snap cutter can't.
- Consistent spacing reduces creeping misalignment that forces extra trimming, so set every joint with tile spacers.
Sharp blades and steady scoring mean fewer cracked tiles, which directly lowers your real-world waste.
The bottom line
Take your room's square footage, then add 10% for a grid, 15% for diagonal or running bond, or up to 20% for herringbone. Buy the whole amount in one dye lot, keep the leftovers, and cut cleanly to stay near the low end of your range.
Let the tile calculator do the arithmetic, then check the grout coverage you'll need to finish the job.