Tile Calculator: Tile Boxes, Flooring, Paint and Wallpaper

Tile boxes, adhesive, paint: the quantities to buy

This calculator works in the units you actually buy: tile boxes depending on the layout (10% waste for straight, 12% for offset, 15% for diagonal), bags of adhesive and grout, 10 L and 2.5 L paint tins, and wallpaper rolls. For 22 m² of 60 × 60 tiles laid straight, you need 17 boxes of 1.44 m², 4 bags of 25 kg adhesive and 2 bags of 5 kg grout.

The three calculations

• Floor: area = length × width, increased by 10, 12 or 15% depending on the layout. Boxes = increased area ÷ m² per box, rounded up. Adhesive = 4.5 kg/m² and grout = 0.4 kg/m² on the net area. The budget applies to the m² actually bought (whole boxes).
• Paint: walls = perimeter × height − 1.8 m² per door − 1.5 m² per window, ceiling included by default. Litres = area × coats ÷ spreading rate × 1.10. The tool suggests 10 L tins, then covers the remainder with 2.5 L tins.
• Wallpaper: drops per roll = roll length ÷ (height + 10 cm), rounded down. Rolls = perimeter × (1 + pattern-match loss) ÷ (drops per roll × roll width), rounded up.

Worked example

A 5.5 × 4 m floor = 22 m² laid straight: 24.2 m², i.e. 17 boxes of 1.44 m² (24.48 m² bought), 68 tiles of 60 × 60, 99 kg of adhesive (4 bags of 25 kg), 9 kg of grout (2 bags of 5 kg). At €29.90/m², €731.95. Laid diagonally: 18 boxes and €775.01. A 5 × 4 m room, 2.50 m high, 2 doors, 2 windows, ceiling included: 58.4 m², two coats, 12.8 L, i.e. 1 tin of 10 L and 2 tins of 2.5 L: the budget covers the 15 L bought, €217.50 at €14.50/L. Wallpaper on 18 m of walls with 10% pattern match: 13 rolls of 0.53 × 10.05 m.

Limits

The adhesive and grout rates are fixed averages for bonded tiles; they do not apply to floating wood floors and vary with tile size and trowel (check the adhesive data sheet). Wallpaper does not deduct openings and adds no spare roll. On raw plaster, choose the porous surface: the amount of paint is multiplied by 1.2 (by 0.95 on a smooth surface). You can also force a single can size, from 0.5 to 10 L. For patterned paper, enter the pattern repeat in cm: it is added to the length of each strip.

Frequently Asked Questions

How many boxes of tiles for 22 m²?

For a straight layout the tool adds 10% waste, i.e. 24.2 m²; with 1.44 m² boxes you need 17 boxes. With an offset or diagonal layout (12% and 15%) it rises to 18 boxes. Enter the coverage per box printed on the packaging, as it varies with tile size.

How much tile adhesive per m²?

The tool counts 4.5 kg of tile adhesive and 0.4 kg of grout per m² of net area. For 22 m², that is 99 kg of adhesive, i.e. 4 bags of 25 kg, and 9 kg of grout, i.e. 2 bags of 5 kg. Large tiles laid with back-buttering use more: check the product data sheet.

Why does a diagonal layout need more tiles?

Every row ends against the wall with an angled cut, and part of the offcuts cannot be reused. The tool applies 15% waste for diagonal against 10% for straight and 12% for offset, which adds about one box on 22 m².

How many rolls of wallpaper for 18 metres of wall?

With a 2.50 m ceiling, each drop is 2.60 m and a 10.05 m roll gives 3 of them, covering 1.59 m of wall. With a 10% pattern-match loss, 19.8 m ÷ 1.59 = 12.5, so 13 rolls. A large pattern repeat calls for a higher loss.

How many liters of paint for a 12 m² bedroom?

For a 4 × 3 m bedroom with 2.50 m ceilings, the walls cover 35 m². After one door and one window (3.3 m²), 31.7 m² remain; with two coats at 10 m²/L and a 10% margin you need 7 liters, i.e. 3 cans of 2.5 L, or 2 cans of 5 L if you pick that size. Including the ceiling, it comes to 9.6 L.

Why does my can of paint cover less than expected?

The coverage printed on the can assumes a smooth, already painted surface. On new plaster or a porous wall, choose "raw plaster": the tool multiplies the amount by 1.2. For the same 31.7 m² bedroom in two coats, it goes from 7 to 8.4 L.

How do I account for the wallpaper pattern repeat?

Enter the repeat shown on the label, in centimeters: it is added to every strip. With 2.40 m ceilings, a 10.05 m roll gives 4 strips of 2.50 m; with a 32 cm repeat, each strip is 2.82 m and the roll gives only 3. For 18 m of walls with a 10% margin, you go from 10 to 13 rolls.

How much area does the tool deduct for a door and a window?

It deducts 1.8 m² per door and 1.5 m² per window from the wall area to paint. Count a bay window or a French window as two windows to get closer to its real size. Wallpaper is worked out over the whole perimeter without deducting openings, because offcuts around a window are rarely reusable.

Is this tool really free?

Yes, all tools on Kristools are 100% free and accessible without registration.

Is my data protected?

Yes. All processing is performed directly and securely inside your browser. No personal data is sent to our servers.