Tile Calculator
Find how many tiles a floor or wall needs from the area and your tile size, with a cutting-waste allowance and box count. Works for any rectangular tile in cm.
How to use this calculator
- Enter the area to tile in m² (length × width of the surface).
- Enter your tile dimensions in cm and how many come per box.
- Use 10% waste for straight layouts, 15% for diagonal or herringbone patterns.
Formula used
Tile area converts to m² by dividing each dimension by 100 (a 30×30 cm tile is 0.09 m²). Waste covers edge cuts, breakages and future repairs; diagonal and patterned layouts generate more offcuts, so use 15%.
Example calculation
12 m² with 30 × 30 cm tiles: each covers 0.09 m², so 12 ÷ 0.09 = 133 tiles exactly. With 10% waste → 147 tiles.
At 11 tiles per box, that's 14 boxes (154 tiles) — leaving 7 spares for future repairs.
Waste and batch matching
Tiling waste isn't optional padding — every edge, corner and obstacle forces cuts, and cut tiles rarely yield usable remainders. Straight grids waste around 10%; diagonal, brick-bond and herringbone layouts push toward 15% because the angled cuts leave more unusable offcuts.
The subtler reason to over-buy is the dye lot: tiles are fired in batches that vary slightly in shade, and boxes from a later purchase may not match. Buying enough in one go — plus a few genuine spares boxed away — is the only reliable insurance against a cracked tile years later standing out against its neighbours.
Why use this calculator?
- Turn area and tile size straight into a box count to order.
- Waste allowance built in for cuts, breakage and repairs.
- See your spare count so you can stash tiles for future fixes.
Frequently asked questions
How many 30x30 tiles in a square metre?
About 11.1 — each 30×30 cm tile covers 0.09 m², so 1 ÷ 0.09 ≈ 11.11 tiles per m². Suppliers usually round to 11 or 12 per m² depending on grout gaps.
How much extra should I buy for tiling?
10% for straight layouts, 15% for diagonal or patterned ones. Always keep a few spares beyond that — matching the exact shade lot later is often impossible.
Does grout spacing change the count?
Slightly — wider grout lines mean fewer tiles per m². This calculator uses the nominal tile size; for large grout gaps (over 5 mm) the effect is small but adds up over big areas, so the waste allowance absorbs it.