🧩 Tile Calculator
Tiles and boxes for a floor or wall: several areas with cut-outs, any tile size and grout joint, waste by layout pattern, cost and grout volume.
Split an L-shaped room into rectangles. Tick “Subtract” for a kitchen island, tub or other area you will not tile.
| Area to tile | 114.0 sq ft · 10.59 m² |
|---|---|
| Coverage per tile (with joint) | 2.031 sq ft |
| Spare tiles after the job | 7 |
| Grout volume (joints only) | ≈ 1.55 L (95 in³) |
Buy all tiles from the same batch (lot number) — color can vary between batches — and keep a few spares for future repairs. Check the grout bag’s coverage chart to turn the grout volume into bags.
What Tile Calculator Does
This tile calculator works out how many tiles and boxes to buy for a floor, wall, backsplash or shower. Add each rectangular area — split an L-shaped room into two — and subtract anything you will not tile, such as a vanity or kitchen island. Enter the tile size and grout joint in inches, or switch to meters and millimeters.
The layout pattern sets a waste allowance — straight and offset layouts waste less than diagonal or herringbone, which need more cuts — and you can change it. With the tiles per box and the box price you get the number of boxes, the total cost, the cost per square foot and how many spare tiles will be left over. It also estimates the volume of grout the joints will take.
How to Use Tile Calculator
- Choose feet and inches, or meters and millimeters
- Enter the length and width of each area, ticking Subtract for cut-outs
- Enter the tile size, grout joint and tile thickness
- Pick the layout pattern to set the waste allowance
- Add tiles per box and price to get boxes and total cost
Formula Used by Tile Calculator
Tiles needed
Tiles = area ÷ ((tile length + joint) × (tile width + joint)) × (1 + waste %)
Worked example
A 12 × 10 ft floor minus a 3 × 2 ft cabinet, 12 × 24-inch tiles, ⅛-inch joints, 10% waste.
- 120 − 6 = 114 sq ft
- 12.125 × 24.125 ÷ 144 = 2.031 sq ft per tile
- 114 ÷ 2.031 = 56.1 tiles × 1.10 = 61.7
Result: Buy 62 tiles — 8 boxes of 8, leaving a few spares.
Grout volume
Grout ≈ tiles × (tile length + tile width) × joint width × joint depth
Worked example
The same floor with ⅜-inch-thick tile.
- 56.1 × 36 × 0.125 × 0.375 = 94.7 in³
- 94.7 in³ × 0.0164 = 1.55 liters
Result: About 1.6 liters of mixed grout, before mixing and cleanup losses.
Tiles per 100 sq ft (⅛″ Joints, Before Waste)
| Tile size | Tiles |
|---|---|
| 4 × 4″ | 847 |
| 3 × 6″ subway | 753 |
| 6 × 6″ | 384 |
| 12 × 12″ | 98 |
| 12 × 24″ | 50 |
| 18 × 18″ | 44 |
| 24 × 24″ | 25 |
| 24 × 48″ | 13 |
Typical Waste Allowances
| Layout | Allowance |
|---|---|
| Straight grid | About 10% |
| Offset / brick | About 10% |
| Diagonal (45°) | About 15% |
| Herringbone | 15–20% |
How to Read Your Result
Plan the layout first
Dry-lay a row from the center of the room to see where the cuts fall; shifting the starting line by half a tile can avoid thin slivers at the walls. More complex layouts use more tile, so if you change the pattern after buying, recheck the count.
Buying whole boxes
Tile is sold by the box, so the count is rounded up to whole boxes. Keep the leftovers and note the lot number printed on the box — color and size can vary between production runs, and an exact match for a repair can be hard to find later.
Walls and backsplashes
For walls, use the height and width of each tiled section and subtract windows and doors. Backsplashes are small areas broken up by outlets and cabinet edges, so cuts make up a larger share of the job; a slightly higher allowance is sensible.
Limitations & Accuracy Notes
- Hexagon, penny-round and other non-rectangular tiles are not modeled exactly; use the square-foot coverage printed on the box instead.
- Grout volume covers the joints only; mixing losses and cleanup mean you need more, so check the bag’s coverage chart.
- Thinset, backer board and trim pieces such as bullnose are not included.