How many tiles do I need? Tiles, grout and flooring boxes

Guide · Updated 2026-11-10

Add up a floor or wall in rectangles, pick a tile size and layout, and get the tiles, boxes and grout to buy, or the boxes of laminate or vinyl planks.

Open the Tile calculator Free, in your browser, nothing uploaded.

Tiles come in boxes, floors come in odd shapes, and some tiles always break or get cut to scraps. The tile calculator turns all of that into one shopping list: the number of tiles, the number of boxes and an estimate of the grout, for any floor or wall you can split into rectangles. A second tab does the same for laminate, vinyl and wood planks sold by area. It suits DIY renovators, small fitters pricing a job, and anyone checking a shop’s estimate. When the same room also gets new paint or paper, the paint calculator and the wallpaper calculator finish the list, and if the floor needs a fresh concrete base first, the concrete calculator works out the volume.

What it is

The count rests on three steps.

Area. Most rooms are rectangles, or rectangles joined together. The tool adds the area of each one (length × width) and subtracts any you mark as Take away, such as a bath, a shower tray or a kitchen island.

Tiles. Divide the area by the area of one tile:

• Exact tiles = A ÷ (l × w), where A is the area to cover and l and w are the tile’s length and width.

Then add the waste share and round up once, at the end:

• Tiles to buy = round up (exact × (1 + waste ÷ 100))

Waste covers the cut pieces at the edges and the odd breakage. Diagonal and herringbone patterns leave more offcuts, so they get more.

Grout. Grout fills the narrow joints between tiles. Around each tile the joint length per square metre depends on the tile size, so the joint volume is:

• Joint volume = (l + w) ÷ (l × w) × gap × thickness × A

Smaller tiles mean more joints per square metre, and more grout. The tool turns that volume into kilograms with a density figure you can change.

The count uses the tile size alone and ignores the space the joints take up, so it always comes out slightly on the generous side.

How to use it

1. Choose the Tiles tab, or Planks (laminate, vinyl, wood) for flooring sold by area.
2. Pick Units: metric (metres, centimetres, millimetres) or imperial (feet, inches). Changing it loads a sample job.
3. Type the length and width of the first rectangle. Press Add a rectangle for each extra part, and set it to Take away for areas you will not cover. Remove drops a row.
4. For tiles, type the tile length and width and pick a Layout. The layout fills in the Waste and cuts (%) box, which you can change.
5. Choose Box sold by (tiles per box, or area per box) and type the figure from the label. Planks always use area per box.
6. Leave Estimate grout ticked and set the gap, tile thickness and kilograms per litre of joint, or untick it to skip grout.
7. Read the total, the boxes and the working lines. Reset to the example starts again.

A worked example

Jo is tiling a bathroom floor 2.2 m by 1.8 m, but the bath (1.7 m by 0.7 m) stays where it is. The tiles are 60 × 30 cm, laid in herringbone, sold 8 to a box. Joints are 2 mm wide and the tiles are 9 mm thick.

• Floor: 2.2 m × 1.8 m = 3.96 m²
• Bath taken away: 1.7 m × 0.7 m = 1.19 m²
• Area to tile: 3.96 − 1.19 = 2.77 m²
• One tile: 0.6 m × 0.3 m = 0.18 m²
• Exact count: 2.77 ÷ 0.18 = 15.4 tiles
• Herringbone, 15% waste: 15.4 × 1.15 = 17.7, rounded up to 18 tiles
• Boxes of 8: 18 ÷ 8 = 2.25, so 3 boxes (24 tiles)
• Grout: about 0.25 L of joint, which at 1.6 kg per litre is about 0.4 kg

The six spare tiles are worth keeping. If one cracks in a year, a tile from the same batch will match the shade.

Next door, Jo lays vinyl planks in a living room 5.2 m by 3.9 m with an alcove 1.2 m by 0.9 m. The area is 20.28 + 1.08 = 21.36 m². With 10% waste that is 23.50 m², and boxes of 1.99 m² make 11.8, so 12 boxes.

Where it is used

• Bathrooms and kitchens, for floors, splashbacks and shower walls (use wall width × height, and take away windows and niches).
• Flooring fitters, who need box counts for laminate, vinyl or engineered wood before ordering.
• Patios and balconies laid with outdoor pavers sold per square metre: use the planks tab with the area per pack.
• Quotes and budgets: multiply the box count by the price per box for the material cost.

Common mistakes

• Rounding twice. Rounding the exact tiles up, then adding waste, then rounding again buys extra tiles for nothing. The tool rounds once, at the end.
• Using the nominal tile size from the shop name. A “30 × 60” tile can measure 29.7 × 59.7 cm. Type the real size from the box for the best count.
• Too little waste in small rooms. A tiny room has more cut edges for its size. Raise the waste share to 15 or 20%.
• Forgetting the wall area under a vanity or behind a toilet. Decide what will be tiled before you measure, then take away only what will truly be hidden.
• Buying grout to the gram. The figure is an estimate; buy the next bag size up, as the tool suggests.

Questions people ask

Can I mix two tile sizes on one floor? Run the tool once for each tile, with the rectangles that each one covers, and add the boxes.

Does a bigger gap need much more grout? Yes, roughly in step. Doubling the gap from 2 mm to 4 mm doubles the grout volume.

Why does the planks tab hide the tile boxes? Planks are sold by area per box, so the tool needs only the floor area, the waste share and what one box covers.