How Many Tiles Do I Need? (Floor & Wall Calculator Guide)
To find how many tiles you need, divide the area (length × width in feet) by the area of one tile in square feet, then add 10–20% for cuts and breakage. A 10×8 ft floor with 12-inch tiles needs about 88 tiles including 10% waste. Always round up to whole boxes and keep a spare box for repairs.
Tile is easy to under-order and expensive to top up later, because dye lots and production runs change between batches. Getting the count right the first time means measuring your area carefully and adding the correct waste allowance for your layout.
This guide shows how to calculate tile counts for both floors and walls, how much waste to add for each pattern, and how to handle borders and irregular rooms so you buy the right amount.
Key takeaways
- Tiles needed = area ÷ tile size, plus waste.
- Add 10% waste for straight lay, 15% diagonal, up to 20% for patterns.
- Tile is sold by the box — round up and keep a spare.
- Measure walls and floors separately for a full bathroom.
- Larger tiles cut waste on open floors; small tiles suit detailed areas.
Skip the math
Get instant numbers with the Tile Calculator.
How to calculate tile quantity
Start with the surface area: multiply length × width in feet for a floor, or height × width for a wall. Then divide by the coverage of a single tile in square feet — a 12-inch tile covers 1 ft², an 18-inch tile covers 2.25 ft². Finally, add a waste factor for cuts and breakage. For irregular rooms, split the space into rectangles, total the areas, then apply waste.
Waste allowance by layout
| Layout | Waste to add | Why |
|---|---|---|
| Straight lay | 10% | Minimal cuts at edges |
| Diagonal | 15% | More angled cuts |
| Herringbone / complex | 15–20% | Many small offcuts |
| Large-format tile | 10–12% | Bigger cuts waste more per tile |
Tiles per 100 square feet
| Tile size | Tiles per 100 ft² | With 10% waste |
|---|---|---|
| 12 × 12 in | 100 | 110 |
| 18 × 18 in | 45 | 50 |
| 24 × 24 in | 25 | 28 |
| 6 × 24 in (plank) | 100 | 110 |
Don't forget the extras
- Buy by the box and round up — partial boxes usually can't be returned.
- Keep one sealed spare box; dye lots change between runs.
- Account for borders, accents, and trim tiles separately.
- For a shower or backsplash, measure each wall and add them up.