A second trip to the merchant for another box of tiles doesn't just cost you money — it costs you a day, and it makes you look like you didn't know what you were doing. The good news is that under-ordering almost always comes down to one of a handful of avoidable mistakes, not bad luck.
1. Measure the room, not the floor plan
Rooms are rarely the neat rectangles they look like on a plan. Alcoves, chimney breasts, door thresholds and out-of-square walls all change the real area you're tiling. Measure the longest length and the longest width of the room, then measure any recesses or awkward sections separately and add them on.
For walls, measure each wall individually rather than assuming they match — especially in older properties, where a 10–15mm difference between "identical" walls is common.
2. Work in a consistent unit, and write it down as you go
Mixing millimetres and metres, or rounding numbers in your head instead of on paper, is one of the most common sources of ordering errors. Record every measurement as you take it rather than trying to remember three or four dimensions until you get back to the van.
This is the exact problem a Leica Disto™ connected to TileIQ solves — the measurement goes straight into the app the moment you take it, so there's nothing to misremember or transcribe wrong later.
3. Always add a waste allowance
Even with a perfect measurement, you'll lose material to cuts, breakages and pattern matching. As a general guide:
- 10% for a straight lay in a simple, mostly rectangular room
- 15% for a diagonal or herringbone lay, or a room with several cuts around fittings
- 15–20% for large-format tiles, natural stone, or a first-time pattern you haven't laid before
Skipping the waste allowance "to save the customer money" is the single biggest reason for a mid-job reorder — and reordering a specific batch can mean a shade or size difference that never quite matches.
4. Don't forget what isn't tiled
Doorways, built-in units, baths, showers and windows all reduce the actual area you need to cover. Measure and subtract these rather than estimating — on a small bathroom, a bath and a vanity unit can easily account for 1–1.5m² you don't need to buy tiles for.
5. Do the material calculation once, properly
Once you have accurate room dimensions and a sensible waste allowance, the actual materials sum — tiles, adhesive, grout, trim — should take seconds, not guesswork. That's exactly what the TileIQ material calculator is built for: enter the room dimensions and tile size, and it works out what you need, including waste, so the order is right the first time.
Measure once, measure properly, and let the calculation do the rest. The tilers who reorder aren't the ones who measure badly — they're the ones who don't write it down.
Keep the measurement, the quote and the job together
The other place accuracy gets lost is between the site visit and the quote — a measurement scribbled on the back of an invoice pad doesn't always make it into the final numbers. In TileIQ, the room measurements feed straight into the quote, so what you measured on site is exactly what gets costed and ordered.