Tile guide
How many tiles do I need?
Ordering too few tiles means a delay and a risk of a different batch shade. Ordering far too many wastes money. The calculation is simple once you know the three numbers that matter: floor area, tile size and a waste allowance that suits your layout.
Last updated
Open the tile layout plannerDraw your room to scale, try tile patterns and see the quantity estimate update.
The tile quantity formula
Tiles needed = (floor area ÷ area of one tile) × (1 + waste allowance), rounded up. Use the tile's nominal size, which already includes the grout joint on most product listings, and work in one unit system from start to finish.
Worked example (metric)
- Room: 4.2 m × 3.1 m = 13.02 m².
- Tile: 600 mm × 300 mm = 0.18 m² each.
- Tiles before waste: 13.02 ÷ 0.18 = 72.3.
- Add 10% waste for a straight layout: 72.3 × 1.10 = 79.6, so order 80 tiles.
- If the same room is laid on the diagonal, add 15% instead: 72.3 × 1.15 = 83.2, so order 84 tiles.
- If a box holds 8 tiles (1.44 m²), that is 10 boxes for the straight layout and 11 boxes for the diagonal one.
Worked example (imperial)
A 12 ft × 14 ft room is 168 sq ft. With 12 in × 12 in tiles (1 sq ft each) and a 10% allowance, you need 168 × 1.10 = 184.8, so order 185 tiles. Always round up to whole tiles, then up again to whole boxes.
How much waste should you add?
| Layout or situation | Typical allowance |
|---|---|
| Straight (grid) layout, regular room | About 10% |
| Diagonal or brick-bond layout | About 15% |
| Herringbone or chevron | 15% to 20%, sometimes more |
| Mosaic or small tiles | 10% to 20% |
| Large-format tiles | More than 10%, because each cut wastes more |
| Small rooms with many cuts and fixtures | 10% to 15% |
L-shaped and awkward rooms
Split the floor into rectangles, calculate each one, then add them together. Subtract areas you will not tile, such as a bath surround or fitted units, but keep your waste allowance on the total because cuts around obstacles produce offcuts.
Buying tips
- Buy everything from the same batch so the shade matches.
- Keep at least one spare box for future repairs.
- Check how many tiles or square metres come in a box before you convert tiles to boxes.
- Allow for the pattern: a layout that needs a centred start or a feature border changes where the cuts fall.
Frequently asked questions
How do I calculate how many tiles I need for a floor?
Multiply room length by width to get the area, divide by the area of one tile, add a waste allowance (about 10% for a straight layout) and round up to whole tiles or boxes.
How much extra tile should I buy?
Around 10% for a straight layout, about 15% for diagonal or brick-bond layouts and 15% to 20% or more for herringbone, mosaics or rooms with many cuts.
Should I include the grout joint in the tile size?
Most suppliers quote nominal tile sizes that already allow for the joint, so use the listed size for a quantity estimate. For precise layouts, work from the actual tile size plus the joint width.
How many boxes of tile do I need?
Divide the total tiles (including waste) by the number of tiles per box, or divide the total area by the coverage per box, then round up to a whole box.
Free, no account needed.