How Much Tile Do I Need? (Calculator + Waste by Pattern)
Quick answer: area in square feet × waste factor, then divide by the area per tile (and per box). A 10×12 ft floor needs 120 sq ft of tile; with 10% waste that's 132 sq ft — or about 132 tiles at 12×12 in. Here's the full method and waste by pattern.
- Tile quantity formula
- Waste by pattern
- Tiles per box
- Worked example
- How to measure walls
- Common mistakes
Tile quantity formula
Tile is sold per box, and each box covers a set area. Start with the floor or wall area, add waste, then divide by the coverage of one box:
Area (sq ft) × (1 + waste%) = tile to buy, then divide by sq ft per box and round up to whole boxes.
Waste by pattern
| Layout | Waste | Why |
|---|---|---|
| Straight / grid | 10% | Cuts at edges and doorways |
| Running bond (offset) | 10–15% | Cut ends along every row |
| Diagonal | 15% | Half-tiles along the perimeter |
| Herringbone / chevron | 15–20% | Angled cuts waste more |
Tiles per box
A common box of 12×12 in tiles covers 10 sq ft (10 tiles). Larger tiles cover more per box: 12×24 in tiles run 8 sq ft per box. Check the box label — it states coverage directly — and always round up so you don't run short mid-floor.
Worked example
- Room = 10 × 12 = 120 sq ft
- Straight layout, 10% waste → 120 × 1.10 = 132 sq ft
- Boxes at 10 sq ft each → 132 ÷ 10 = 13.2 → 14 boxes
How to measure walls
For a backsplash or full wall, measure width × height of each wall section and add them. Subtract the area of windows and outlets (roughly). A 4×8 ft backsplash is 32 sq ft; with 10% waste that's 35.2 sq ft of tile to buy.
Common mistakes
- Skipping waste. Grout lines and cuts always add up.
- Buying per tile, not per box. Tile comes boxed — round to whole boxes.
- Not buying extra for repairs. Keep 1–2 spare tiles; dye lots and discontinued lines make matching hard later.
- Mixing measurement units. Work in inches or feet consistently, then convert.
FAQ
A 100 sq ft floor at 12×12 in tiles needs 100 tiles before waste. Add 10% waste for 110 tiles, which is 11 boxes at 10 tiles per box.
Add 10% for a straight layout, 10–15% for running bond, and 15–20% for diagonal or herringbone patterns because angled cuts waste more tile.
A box of 12×12 in tiles typically covers 10 sq ft (10 tiles). Larger formats like 12×24 in run about 8 sq ft per box. Check the box label for exact coverage.
Yes, order about 10% extra even for a small bath. Wet rooms need spare tiles for repairs, and it's far cheaper to buy one extra box now than to match a discontinued line later.
Coverage by tile size
Different tile sizes cover different areas per tile and per box. A quick reference (nominal sizes, coverage per tile):
| Tile size | Area per tile | Typical per box |
|---|---|---|
| 4×4 in | 0.11 sq ft | ~5 sq ft |
| 6×6 in | 0.25 sq ft | ~7.5 sq ft |
| 8×8 in | 0.44 sq ft | ~8 sq ft |
| 12×12 in | 1 sq ft | 10 sq ft |
| 12×24 in | 2 sq ft | 8 sq ft |
| 24×24 in | 4 sq ft | 16 sq ft |
Manual tile count (per tile)
If you're counting individual tiles, work in inches: area in sq in ÷ area of one tile = tiles. For a 120 sq ft (17,280 sq in) floor with 12×12 (144 sq in) tiles: 17,280 ÷ 144 = 120 tiles, plus 10% waste = 132. Divide by tiles per box and round up. This matches the calculator and is handy when you're pricing a specific tile not sold by the box.
Measuring tips for walls and floors
- Measure in inches for odd-shaped spaces, then convert to square feet (÷144).
- Split L-shaped or irregular rooms into rectangles and add them.
- For walls, measure each section width × height and subtract windows/outlets.
- Add a small buffer for doorways and edges you'll cut around.
Tile cost & related materials
Tile itself ranges widely — ceramic runs about $1–$5 per sq ft, porcelain $2–$8, and natural stone $5–$20+. On top of tile, budget thinset, grout, and backer board. A rough materials-only budget is tile + 10–15% for thinset/grout/board. Use the grout guide to size the grout for your joint width.