Current for 2026•As of: July 2026

Tile Calculator calculate number of tiles with waste.

Enter area, tile format and waste allowance – get the exact quantity instantly

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Tile Calculator

Calculate the number of tiles including waste allowance – for bathroom, kitchen, floor and wall.

1 m²100 m²
5 cm120 cm
5 cm120 cm

Area per tile: 0.0900 m²

Waste allowance (%)

Diagonal laying: 15–20%, straight: 10%, professional: 5%

Tiles needed

245 tiles

incl. 10% waste allowance

Net + waste

  • Net tiles(91 %)223 tiles
  • Waste (10%)(9 %)22 tiles

Calculating tiles: formula, waste allowance and practical tips

Buying too few means a delivery delay, buying too many costs money – the formula explained

The tile formula is: quantity = ⌈area ÷ tile area × (1 + waste/100)⌉. For 20 m² and a tile of 30 × 30 cm (individual area 0.09 m²) with 10% waste, this gives: ⌈20 ÷ 0.09 × 1.10⌉ = ⌈244.4⌉ = 245 tiles. A 10% waste allowance is the recommended standard value for straight-laid tiles in a rectangular room.

Why waste is unavoidable: Cut-offs occur at every wall because room dimensions are rarely an exact multiple of the tile format. Corners, cutouts for sanitary fixtures, door frames and irregular room shapes further increase waste. Tiles laid diagonally (45°) produce noticeably more waste due to the angled cut lines at the edges – here 15–20% is realistic.

Grout pattern and tile adhesive: Besides the number of tiles, you need tile adhesive (also: thin-set mortar), grout and spacers. Tile adhesive is specified in kg/m² – typically 3–5 kg/m² with a 6–8 mm notch trowel. For floor tiles in wet areas, a flexible adhesive (C2F) is mandatory. Grout width affects the visual result: 2 mm for porcelain stoneware, 4–8 mm for handmade or rustic tiles.

Buy a reserve, same batch: Always buy 5–10 tiles more than calculated and keep them in reserve. Tiles are produced in batches – shade differences are possible when buying more from a different batch later. A reserve also protects against breakage during installation or later repairs. Broken or cracked tiles must be replaced before moisture gets under the floor.

Waste recommendations by installation method

Typical waste depending on installation and format

Straight laying: 10%
Standard for rectangular rooms; experienced DIYers may manage 8%
Diagonal laying (45°): 15–20%
More cutting waste along all four walls; more demanding for beginners
Herringbone pattern: 15%
Classic parquet-style pattern for elongated tiles (e.g. metro tiles)
Large format ≥ 60×60 cm: 10%
Fewer tiles, but heavier cuts; fewer grout lines
Mosaic < 10×10 cm: 12–15%
Many cuts, labor-intensive; often supplied on mesh sheets (calculate m²)
Irregular rooms: +5%
Niches, slopes and cutouts always increase waste

Calculation examples

Bathroom 20 m², tile 30×30 cm, 10% waste

Bathroom 20 m², tile 30×30 cm, 10% waste
ItemAmount
Area20.00 m²
Tile area (0.30 × 0.30)0.09 m²
÷ 0.09 × 1.10244.44
Rounded up245 tiles

Kitchen floor 12 m², tile 60×60 cm, 5% waste

Kitchen floor 12 m², tile 60×60 cm, 5% waste
ItemAmount
Area12.00 m²
Tile area (0.60 × 0.60)0.36 m²
÷ 0.36 × 1.0535.0
Rounded up36 tiles

Frequently asked questions about the tile calculator

Waste allowance, formats and costs for your tiling project

The waste allowance depends on the installation method and format. For straight laying (parallel to the walls), a 10% surcharge is usually enough. For diagonal laying (45°), waste increases to 15–20%, since more material has to be cut off at the walls. For smaller formats under 15 × 15 cm, waste can also increase due to more cuts. For professionals and experienced DIYers working on simple areas, 5–8% is often enough.

The net tile count is the area in m² divided by the tile area in m². A 20 m² area with 30 × 30 cm tiles (0.09 m²) gives 222.2 → rounded up to 223 tiles without waste. With 10% waste, our calculator arrives at 245 tiles. The difference (22 tiles) corresponds to about 10% and covers typical cutting losses at walls, corners and cutouts.

Classic formats are 20 × 20 cm, 25 × 25 cm and 30 × 30 cm. Modern bathrooms often use large-format tiles (60 × 60 cm, 60 × 120 cm or 80 × 80 cm). Large-format tiles have fewer grout lines and look more spacious, but are harder to install and require a perfectly level surface. Metro tiles (7.5 × 15 cm) are popular for kitchen splash-back areas.

Tiles are indivisible units – you cannot buy 0.4 of a tile. That is why the calculated quantity is always rounded up to the next whole tile (ceiling function). It is also recommended to buy 2–5 extra tiles as a reserve. In case of damage or breakage, a reserve from the same batch (same pattern, same shade) is invaluable.

In Germany, tradesperson costs for tile installation in 2025 range from €35–70 per m² depending on region (labor only, no material). Simple floor tiles in straight layout are cheaper than wall tiles or diagonal patterns. In addition, there are material costs for tile adhesive (€3–8/m²), grout (€2–5/m²) and cutting. As a DIYer, you save the labor share – but need a tile cutter, trowel and spacers.

Sources & calculation basis

Our calculations are based on the following official sources (as of: July 2026):

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