How Many Tiles Do I Need? UK Guide with Adhesive and Grout
A 3 × 2.5 m floor in 300 × 300 mm tiles with 3 mm joints needs 90 tiles (9 boxes), about 37 kg of adhesive and 2.9 kg of grout, allowing 10% for cuts. Here is the full list, with a chart for other rooms and tile sizes.
The materials list for a 3 × 2.5 m floor
| What to buy | How much | How we worked it out |
|---|---|---|
| Tiles, 300 × 300 mm | 90 tiles (9 boxes of 1 m²) | Tile calculator: 7.5 m² with 3 mm joints, plus 10% for cuts. Buy a spare box |
| Flexible tile adhesive | 37 kg (2 bags of 20 kg) | A 10 mm notched trowel, about 4.5 kg per m², plus 10% for the skim coat and spillage |
| Grout | 2.9 kg (1 bag of 5 kg) | The volume of the joints for 10 mm thick tiles, at 1.6 kg per litre, plus 20%. A 2.5 kg bag would give 2 bags |
| Primer and a tanking kit | As needed | A primer for absorbent boards, and a waterproofing (tanking) system in a wet room or shower |
| Spacers and trowels | 1 pack and 1 trowel | 3 mm spacers for these joints, a notched trowel, a grout float and a sponge |
| Trim and sealant | As needed | Edge trim for outside corners, and silicone sealant for the joint against the bath, basin or shower tray |
Tiles for common rooms and tile sizes
3 mm joints and 10% for cuts. Count the number of tiles, and then check the boxes against the coverage printed on the box:
| Room | 300 × 300 mm | 450 × 450 mm | 600 × 600 mm | 600 × 300 mm |
|---|---|---|---|---|
| Small bathroom floor (2 × 1.5 m) | 36 | 17 | 10 | 19 |
| Kitchen floor (3 × 2.5 m) | 90 | 41 | 23 | 46 |
| Living room (4 × 3 m) | 144 | 65 | 37 | 73 |
| Large living area (5 × 4 m) | 240 | 108 | 61 | 121 |
How the tile size changes the adhesive and grout
For the same 3 × 2.5 m floor. Large tiles use a bigger trowel, so more adhesive, but have fewer joints, so less grout:
| Tile size | Tiles | Adhesive | Grout |
|---|---|---|---|
| 300 × 300 mm | 90 | 37 kg | 2.9 kg |
| 450 × 450 mm | 41 | 50 kg | 1.9 kg |
| 600 × 600 mm | 23 | 50 kg | 1.4 kg |
| 600 × 300 mm | 46 | 50 kg | 2.2 kg |
What about walls?
Measure the width and the height of each wall and add them up, then take off any large windows or doors. For 8 m² of wall tiled in 600 × 300 mm tiles with 3 mm joints, you need 49 tiles (9 boxes at 1.08 m² a box), about 26 kg of adhesive with a 6 mm trowel and 1.8 kg of grout. Use the calculator with the wall figures for your own walls.
Before you buy
- Check the base. A floor must be flat (within about 3 mm over 2 m), firm, clean and dry. A new screed needs to dry first, and a timber floor needs to be overboarded with tile backer boards.
- Choose the right adhesive. Use a flexible adhesive over underfloor heating, on timber floors and for large or porcelain tiles. A rapid-set product speeds things up but gives you less time to adjust.
- Buy from one batch, and check the shade on each box before you open it.
- Plan the layout. Dry-lay a row across the room, and set out from the centre so that the cuts at both walls are equal and not thin slivers.
Mistakes that cost people money
- Ordering exactly the floor area. Cuts and breakages mean you always need some extra.
- Using a trowel that is too small for the tile, which leaves voids under the tile that crack.
- Grouting too early. Follow the adhesive maker's time, usually 24 hours.
- Forgetting the movement joints in a large floor, and the flexible sealant at the edges.
Frequently asked questions
How many tiles do I need for 10 square metres?
120 tiles of 300 × 300 mm with 3 mm joints and 10% for cuts. Larger tiles need fewer, so check the chart above.
How many tiles do I need for a 3m x 2.5m kitchen floor?
90 tiles of 300 × 300 mm (9 boxes at 1 m² a box), allowing 10% for cuts. Without waste it is 82.
How much adhesive and grout do I need?
For the 3 × 2.5 m floor about 37 kg of adhesive (2 bags of 20 kg) and 2.9 kg of grout (1 bag of 5 kg).
How much extra tile should I buy?
10% for a straight layout, 15% for diagonal layouts, large tiles or patterns, and an extra box to keep for repairs.
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Estimates only. Quantities depend on your materials, site and supplier. Confirm important numbers before you order, and check the Building Regulations and any planning rules for anything structural or close to a boundary.