Tile Quantity and Cost Calculator

Tiling a kitchen extension floor and splashback typically costs £80 – £120 per m² installed in mid-range porcelain, and this calculator breaks that number into the parts you actually order: tiles, adhesive, grout, and a tiler's labour. Enter your floor area, wall or splashback area, tile size, and price per m², and it returns tile counts, bag quantities for adhesive and grout, and a fitting budget range.

The all-in rate above is the standard cost per m² benchmark for a finished porcelain floor. The calculator lets you split it, so you can price tiles you supply yourself against a tiler's labour-only quote, or sanity-check a builder who has bundled the whole job into one line.

What tiling costs per m²

Tiler labour for a floor runs £30 – £60 per m². Wall and splashback tiling sits a little higher per m² than that, because working off ladders and keeping tiles level is slower than laying a floor. Mid-range porcelain floor tiles themselves cost £20 – £60 per m2 to supply, and adhesive with grout adds £8 – £12 per m² on top. Put those together and a professionally finished floor lands at £80 – £120 per m², which is the figure most quotes should sit near.

Over underfloor heating, add a decoupling membrane at £10 – £12 per m². It absorbs the movement from heating cycles so the tiles do not crack, and a good tiler treats it as non-negotiable rather than an upsell.

How the calculator counts tiles and materials

Tile count comes from your area divided by the coverage of a single tile, plus a wastage allowance for cuts around reveals, breakages, and setting-out offcuts. The default allowance suits a straight lay; push it higher for diagonal patterns or a room with many cuts. Adhesive is estimated from total area, and grout from area adjusted for tile size, since larger tiles have fewer joints to fill.

Tile size changes more than the count. Larger formats use less adhesive per m² but demand a flatter substrate, and under BS 5385 anything above a modest size needs solid-bed fixing with full adhesive contact rather than dabs. That is why the tile-size choice in the calculator affects both your bag quantities and how forgiving the job is to lay.

A worked example

Take a 30m² single-storey extension floor in mid-range porcelain. Tiler labour at £30 – £60 per m² sets the fitting range the calculator shows above, and tiles at £20 – £60 per m2 plus adhesive and grout at £8 – £12 per m² give the supply side. Add a membrane if the floor is heated, then round up to whole packs and bags.

On a documented 55m² extension in the South East, a tiler laid 81m² of floor and wall in porcelain. The tiler's labour came in at £38 per m², the lower end of the £30 – £60 per m² market range, helped by a large single floor. All in, the job worked out at £87 per m² for a total of £7,033, which sits comfortably inside the £6,000 – £8,000 you would expect for a floor of that size. See the tiling guide for the sequence, adhesive types, and the checks that keep a floor from lifting later.