Tile Calculator
Tiles and packs for a floor or a wall, grout joint included.
How it works
Tile counts are worked out from the tile plus its grout joint, not the tile alone. A 300 × 300 tile with a 2 mm joint effectively occupies 302 × 302, which sounds negligible and is worth roughly one tile in every hundred.
The waste allowance matters more than the joint. Ten percent covers a straightforward straight lay; a diagonal layout, a small bathroom full of cuts, or large-format tiles that break easily can push it to 15% or more. Buy the whole quantity in one go — dye lots differ between batches, and a replacement pack bought later rarely matches.
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How the Tile Calculator works
A tile calculator works out how many tiles and packs a floor or wall needs. It accounts for the grout joint and the cutting allowance — the two things that make a plain area-based estimate come out short.
The joint is part of the calculation
A tile occupies not its nominal size but its size plus the joint. A 300 × 300 tile with a 2 mm joint effectively sits in a 302 × 302 grid. The difference looks negligible and costs roughly one tile in every hundred — over a large area, a whole pack.
The smaller the format the more the joint matters: with mosaic it can absorb a tenth of the area. With large-format tile the effect is almost invisible.
Why ten percent is not always enough
Ten percent covers a straight lay in a regular room. A diagonal layout needs fifteen or more, since every tile at the wall is cut at an angle and the offcut rarely gets reused. A small bathroom with cuts around the whole perimeter also goes past ten.
Breakage is a separate line. Large-format tile cracks during cutting noticeably more often than small, and 20 mm porcelain takes experience. Above all, buy the whole quantity in one batch: dye lots differ, and a pack bought a month later will show on the wall.
FAQ
How much tile does a bathroom need?expand_more
Take the wall area as perimeter times tiling height, subtract the door, add the floor area. Then add 10–15% — bathrooms always involve heavy cutting around boxing, niches and sanitaryware.
What joint width should I use?expand_more
1.5–2 mm for wall tile, 2–3 mm for floor tile, and 1.5 mm is possible for rectified porcelain. Never lay with no joint at all: tiles have a dimensional tolerance and the substrate moves with temperature and humidity.
Should I calculate tile by area or by count?expand_more
By count. Tile is sold in packs, and the coverage printed on a pack is rounded. Working in tiles and then rounding up to whole packs gives the right answer; working in square metres consistently under-orders.