About this calculator
This calculator answers how many tiles a wall needs to be covered — enter the wall dimensions, the tile size, and the joint width, and add any openings (doors, windows) separately so they are deducted from the calculated area. Useful for planning tiles for a bathroom, kitchen, or any other wall.
Formula
The calculator converts the wall and tile dimensions to whole millimetres, then:
wall area = length × height
openings area = Σ (opening width × opening height)
net area = wall area − openings area
tile "pitch" = (tile length + joint width) × (tile width + joint width)
tiles required (excl. waste) = ceil(net area / pitch)
waste tiles = ceil(tile count × waste% / 100)
total tiles = tile count + waste tiles
Openings are deducted as net area, not as individual tile subtraction — this stays exact regardless of how an opening crosses the tile grid. Each opening is checked so that its sill height plus its own height cannot exceed the wall height (error if it does), and the total openings area cannot exceed the wall area (also an error).
Adhesive quantity: net area × adhesive coverage (kg/m²). Grout (joint) quantity is
computed from exact geometry — within one pitch "cell", the joint area is pitch - tile area; that fraction, multiplied by the joint depth and density, gives the mass. Neither the
adhesive coverage nor the grout density comes from a standard or a manufacturer figure —
both are user inputs with sensible defaults.
Worked example
Defaults: wall length 4 m, height 2.5 m, no openings, tile 300×300 mm, joint 3 mm, waste 10%, adhesive coverage 4 kg/m², joint depth 8 mm, grout density 1.6 kg/l.
wall area = 4 m × 2.5 m = 10 m² (no openings, so net area is the same)
pitch = (300+3) mm × (300+3) mm = 303 × 303 = 91,809 mm²
tiles per m² = round(1,000,000 / 91,809) = 11
tiles excl. waste = ceil(10,000,000 / 91,809) = 109
waste tiles = ceil(109 × 10 / 100) = 11
total tiles = 109 + 11 = 120
adhesive = 10,000,000 mm² × 4 kg/m² = 40,000,000 mg = 40 kg
joint area per cell = 91,809 - (300×300) = 1,809 mm²
grout ≈ 2,522,106 mg ≈ 2.52 kg
For these inputs the calculator returns exactly this: 120 tiles total (109 excl. waste + 11 for waste), 11 tiles/m², 40 kg of adhesive, and about 2.52 kg of grout.
FAQ
Are openings (doors, windows) deducted from the tile quantity? Yes. Every added opening is deducted from the wall area before the tile quantity is computed — this differs from the wallpaper calculator, where strip count doesn't deduct openings.
How much waste should be allowed for tiling? The default is 10%, adjustable from 0 to 50. The real requirement depends on the laying pattern, cutting at corners, and tile size.
Why does the calculator warn about the joint width? When the joint is thinner than 1.5 mm or thicker than 12 mm, a warning is shown — this is only a practical guideline (a thin joint is typical for rectified tile, a wide one for natural stone), not a limit: the calculator still uses exactly the value you entered.
What determines the adhesive and grout coverage? Adhesive coverage (kg/m²) and grout density (kg/l) are values you enter, with sensible defaults — not from a standard or a specific product's data — they depend on trowel notch size, tile size, and the specific product.
Does the drawing show the exact tile layout? For a large wall (many rows or columns), the drawing is simplified to stay legible — in that case a warning is shown noting the drawing is schematic.
Assumptions and limits
No standard was found for a tile quantity/area calculation — it's a plain geometric problem,
not an engineering calculation, so meta.standards is deliberately left empty.
Adhesive coverage (kg/m²), joint depth, and grout density (kg/l) are user inputs with sensible defaults, not constants derived from a standard — real consumption depends on the specific product and trowel notch size.
Tiling is modeled as a straight grid with no "running bond" offset — unlike the masonry-wall calculator, joints here are always aligned. The drawing shows tiles to scale, including cut tiles at the edges, but the total quantity is always calculated from area, not a count of the tiles drawn. The drawing is also schematic: for a large area, the row/column count is decimated so the SVG stays legible and small — neither affects the tile quantity calculation itself.