Whether you’re tiling a bathroom floor, a kitchen backsplash or a whole living room, this calculator tells you how many tiles and boxes to buy – including extra for cuts and breakage.
The calculation
- Area to tile = length × width (in sq ft).
- Area of one tile = tile width × tile length ÷ 144 (inches to sq ft).
- Tiles = area ÷ tile area, plus a waste percentage, rounded up.
- Boxes = tiles ÷ tiles per box, rounded up.
Example
A 12 × 10 ft room (120 sq ft) with 12 × 24 inch tiles (2 sq ft each) needs 60 tiles. With 10% extra that’s 66 tiles; at 8 tiles per box, buy 9 boxes.
How much waste to allow
| Layout | Extra |
|---|---|
| Straight / grid, simple room | 10% |
| Brick / offset pattern | 10–15% |
| Diagonal | 15% |
| Herringbone or chevron | 15–20% |
| Natural stone / handmade tile | 15–20% |
Tips
- Buy all tiles from the same batch / dye lot – colours vary between batches.
- Keep a few spare tiles for future repairs.
- For L-shaped rooms, split the floor into rectangles, calculate each, and add them up.
- Large-format tiles (24 inches and up) need a flatter floor and more careful planning around cuts.
Tiles needed for common room sizes (with 10% extra)
| Room | Area | 12×12 in tiles | 12×24 in tiles | 24×24 in tiles |
|---|---|---|---|---|
| 5 × 8 ft bathroom | 40 sq ft | 44 | 22 | 11 |
| 10 × 10 ft | 100 sq ft | 111 | 56 | 28 |
| 12 × 12 ft | 144 sq ft | 159 | 80 | 40 |
| 12 × 15 ft | 180 sq ft | 199 | 100 | 50 |
| 15 × 20 ft | 300 sq ft | 330 | 165 | 83 |
Metric example
A 3.5 m × 2.8 m kitchen floor is 9.8 m². With 600 × 600 mm tiles (0.36 m² each), you need 9.8 ÷ 0.36 = 27.2 tiles, or 30 with 10% extra. In the calculator, enter 11.48 × 9.19 ft and 23.6 × 23.6 inch tiles for the same result.
Wall tiling
For walls, multiply width by the height you’ll tile, and subtract windows and doors. A typical bathtub surround (three walls, 5 ft high) is around 60–75 sq ft. Backsplashes are usually 18 inches high – a 10 ft run is 15 sq ft.
Other materials you’ll need
- Thinset / tile adhesive: a 50 lb bag typically covers 40–95 sq ft depending on trowel size and tile size – large tiles need more.
- Grout: depends on joint width and tile size; a 25 lb bag of sanded grout covers roughly 100–400 sq ft.
- Spacers, levelling clips (for large-format tiles), a notched trowel, a tile cutter or wet saw.
- Underlayment or backer board for floors and wet areas.
Plan the layout first
- Start from the centre of the room so cut tiles at opposite walls are equal.
- Avoid slivers – if the last row would be less than half a tile, shift the starting line.
- For rectangular tiles in an offset pattern, a 1/3 offset reduces lippage compared with a 50% offset.
Real-life scenarios
- Bathroom floor: A 6 × 9 ft bathroom (54 sq ft) with 12 × 24 inch porcelain needs 30 tiles with 10% waste – 4 boxes of 8.
- Herringbone hallway: A 4 × 20 ft hallway (80 sq ft) in 6 × 24 inch planks needs 80 ÷ 1 = 80 tiles plus 20% for the pattern = 96 tiles.
- Kitchen backsplash: 14 ft of counter with an 18-inch backsplash is 21 sq ft. With 3 × 6 inch subway tiles (0.125 sq ft each), you need 168 tiles plus 10% = 185.
Related calculators
- Square footage calculator – measure any room
- Paint calculator – walls after tiling
- Concrete calculator – for slabs
FAQs
How many tiles in a box?
It varies by size: 12×12 tiles often come 10–15 per box, 12×24 tiles 6–8, and 24×24 tiles 3–4. Always check the box label for square footage per box.
Can I return extra tiles?
Many stores accept unopened boxes. Keep one box for future repairs anyway.
How many tiles are in a square metre?
1 m² = 10.76 sq ft. For 600 × 600 mm (≈ 24 × 24 inch) tiles, that’s about 2.8 tiles per m².
Should I include grout lines?
Grout lines are small enough that the waste allowance covers them.
Need the total area first? Use the square footage calculator.