Tile Calculator
Calculate how many tiles, adhesive and grout you need. Enter your area, tile size, and laying pattern. Includes wastage allowance and cost estimates.
Room Dimensions
Tile Size
Coverage & Packaging
Pricing
Results
Floor Area
12.00 m²
Tile Size
450×450mm
0.2025 m² per tile
Tile Count
Cost
How Many Tiles You Actually Need
Floor area divided by tile area gives the bare minimum. The defaults here, a 4 m by 3 m kitchen with 450 mm by 450 mm tiles, work out at 12 sq m of floor and roughly 60 tiles before any wastage. Add the standard 10% allowance and the order rises to 66 tiles, which at 10 tiles per box rounds up to 7 boxes. That spare partial box is the buffer for breakages, off-cuts at the door threshold, and the inevitable chip when the diamond blade slips on the last cut.
Different tile sizes change the maths in surprising ways. Going from 300 mm to 600 mm tiles cuts the count fourfold for the same area, but each cut wastes more material because the off-cuts are bigger. Mosaics on a 300 mm sheet behave more like wallpaper than tile when it comes to allowance. For walls with a feature pattern or for a herringbone lay, push the wastage to 15% before you order.
Cost, Adhesive and Grout Often Get Forgotten
Floor tile prices in the UK range from about £15 per square metre at the budget end (plain ceramic, glazed) up to £80 or more for porcelain large-format and natural stone. The calculator takes per-tile or per-box pricing and totals the project, but the supplier line on the receipt is rarely the full bill. A 12 sq m floor needs roughly two 20 kg bags of flexible adhesive (about £30 each) and a 5 kg bag of grout (£15). Levelling clips and spacers add a tenner.
If the substrate is timber or an unstable screed, an uncoupling membrane is the difference between a floor that lasts twenty years and one that cracks in two winters. That layer adds £15 to £25 per square metre and is non-negotiable in bathrooms over joists. For paint and wall finishes near the tile line, [Paint Calculator](/paint-calculator) handles the trim coverage.
Frequently Asked Questions
How much wastage should I allow for tiles?
10% is standard for a straight grid layout in a simple square or rectangle. For diagonal lays, herringbone or pattern repeats, allow 15%. For complex bathrooms with multiple cuts around toilets, vanities and pipes, push to 20%. Returning unopened boxes is usually possible; running out mid-job is much worse.
How many tiles fit in a square metre?
It depends on tile size. A 300 mm tile gives 11.1 per square metre, a 450 mm tile gives 4.9, a 600 mm tile gives 2.78. Trade counters usually quote coverage per box rather than tile count; one 10-tile box of 450 mm tiles covers about 2 sq m.
How much adhesive and grout do I need?
Standard rule of thumb is one 20 kg bag of tile adhesive per 4 to 5 sq m for floor tiles, or one bag per 6 to 8 sq m for walls. A 5 kg bag of grout covers around 8 to 10 sq m of standard 6 mm joints. Wider joints and larger tiles use more grout.
Should I buy tiles with the same batch number?
Yes. Even within a single design, dye lots vary slightly between batches. Buying enough on day one to finish the job, including the wastage allowance, avoids the heartbreak of finishing a wall with a noticeably different shade across the grout line. Keep a spare box for future repairs.
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