How Many Tiles Do I Need?
Short answer: work out the area in square metres, divide by the area of one tile, then add 10% for cuts and breakages. A 600 × 300 mm tile covers 0.18 m², so you need 5.56 tiles per m², or about 6.1 per m² with 10% waste. A 12 m² kitchen floor takes 74 of those tiles.
The tile formula
UK tiles are sold by size in millimetres, so convert the tile to square metres first. Then divide the area you are tiling by the area of one tile and add a waste allowance.
Tile area (m²) = tile length (mm) × tile width (mm) ÷ 1,000,000
Tiles = area ÷ tile area × (1 + waste %), rounded up
Our calculator rounds the tile count up to a whole tile and then rounds the boxes up too. It ignores grout joints, which take up a little space and make the real count very slightly lower, so the figure errs on the safe side.
Tiles per square metre by size
| Tile size | Area of one tile | Tiles per m² | With 10% waste | With 15% waste |
|---|---|---|---|---|
| 100 × 100 mm | 0.01 m² | 100 | 110 | 115 |
| 200 × 100 mm (metro) | 0.02 m² | 50 | 55 | 57.5 |
| 300 × 300 mm | 0.09 m² | 11.11 | 12.22 | 12.78 |
| 600 × 300 mm | 0.18 m² | 5.56 | 6.11 | 6.39 |
| 600 × 600 mm | 0.36 m² | 2.78 | 3.06 | 3.19 |
| 800 × 800 mm | 0.64 m² | 1.56 | 1.72 | 1.80 |
| 1200 × 600 mm | 0.72 m² | 1.39 | 1.53 | 1.60 |
Multiply the "with waste" figure by your area for a quick estimate, then round up. The tables below do that rounding for you.
Tiles for common UK jobs
All counts include 10% waste and are rounded up to whole tiles.
| Job | Area | 300 × 300 mm | 600 × 300 mm | 600 × 600 mm |
|---|---|---|---|---|
| Kitchen splashback, 3 m × 0.6 m | 1.8 m² | 22 | 11 | 6 |
| Downstairs WC floor, 1.5 m × 1.2 m | 1.8 m² | 22 | 11 | 6 |
| Walls round a bath, 2.4 m run × 1.2 m high | 2.88 m² | 36 | 18 | 9 |
| Bathroom floor, 2 m × 1.8 m | 3.6 m² | 44 | 22 | 11 |
| Hallway, 4 m × 1.2 m | 4.8 m² | 59 | 30 | 15 |
| Floor of 10 m² | 10 m² | 123 | 62 | 31 |
| Kitchen floor, 4 m × 3 m | 12 m² | 147 | 74 | 37 |
| Floor of 20 m² | 20 m² | 245 | 123 | 62 |
A metro splashback works the same way: 1.8 m² of 200 × 100 mm tiles is 90 tiles before waste, or 99 with 10%. At 50 tiles a box that is 2 boxes.
How much waste to allow
Waste covers cut tiles at the edges, breakages and offcuts you cannot reuse. For the same 12 m² kitchen floor in 600 × 300 mm tiles, sold in boxes of 6:
| Waste allowance | When to use it | Tiles | Boxes of 6 |
|---|---|---|---|
| 0% | Never, unless you have spares already | 67 | 12 |
| 5% | Large, simple rectangle with few cuts | 70 | 12 |
| 10% | Straight or brick-bond lay (the usual choice) | 74 | 13 |
| 15% | Diagonal or herringbone pattern | 77 | 13 |
| 20% | Small room with lots of corners, pipes and cuts | 80 | 14 |
Because tiles come in whole boxes, going from 10% to 15% here does not add a box. It often pays to check whether a slightly higher waste figure still fits in the same number of boxes.
Worked example: a small bathroom floor
The floor is 2.2 m × 1.7 m = 3.74 m². You have chosen 300 × 300 mm tiles, which are 0.09 m² each.
3.74 ÷ 0.09 = 41.6 tiles. Add 10% waste: 41.6 × 1.1 = 45.7, so buy 46 tiles. If the tiles come 11 to a box, 46 ÷ 11 = 4.2, so you need 5 boxes (55 tiles), which leaves 9 spares. At an example price of £24 a box, that is £120. A herringbone layout at 15% would need 48 tiles, which still fits in the same 5 boxes.
Practical tips
- Measure each area separately. For an L-shaped room, split it into rectangles, work out each one and add them up. Take out large areas you will not tile, such as under a fitted bath.
- Check the box, not just the tile. Boxes are often sold by the square metre covered. Divide your area (with waste) by the m² per box to get the box count directly.
- Same batch number. Colour can vary between production batches, so buy everything at once and check the batch code on each box.
- Keep spares. Store a few leftover tiles. Matching a discontinued tile years later for a repair is hard.
- Adhesive and grout. These are bought by the area too. If you are laying a new floor base first, the square metre calculator helps, and for the walls around new tiles see how much paint you need for a room.
Try the tile calculator (m² and boxes)
Enter your own numbers below, or open the full tile calculator (m² and boxes) with the formula and more examples.
This guide is general information with example numbers, not financial, tax or building advice. Your costs and results will differ. Terms
Frequently asked questions
How many 600 × 600 tiles do I need for 10 square metres?
10 m² divided by 0.36 m² is 27.8 tiles, or 31 tiles with 10% waste.
How many 300 × 300 tiles are in a square metre?
11.11 tiles, because each one covers 0.09 m². With 10% waste allow about 12.2 tiles per m².
How many tiles do I need for 20 m²?
With 600 × 300 mm tiles, 123 tiles including 10% waste. With 600 × 600 mm tiles, 62 tiles.
Should I add 10% or 15% extra tiles?
10% for a straight or brick-bond layout. 15% for diagonal or herringbone patterns, and up to 20% for small rooms with lots of cuts.