The short version: measure the area you're tiling in square metres, add 10% for cuts and breakages, then divide by the coverage of one box. Round up to whole boxes. Every tile product on this site has a calculator built into the page that does this for you.
Step 1: Measure the Area
Floors. Multiply length by width in metres. A room 3.5m by 4.2m is 14.7m². For an L-shaped room, split it into rectangles, work each out separately and add them together.
Walls. Measure each wall's width and height separately and add the results. A wall 2.4m wide by 2.5m high is 6m². Do that for each wall you're tiling rather than trying to treat the room as one figure.
Windows and doors. Only subtract openings larger than about 1m². Anything smaller, leave in — the offcuts around a small window rarely give you usable tiles, so the extra material is genuinely needed.
Step 2: Add for Wastage
You will always need more tiles than the bare area, because tiles get cut at edges, corners and around pipework, and cuts go wrong.
- 10% — the standard allowance for a straightforward square or rectangular room, tiles laid straight.
- 15% — diagonal layouts, herringbone, or a room with several corners, alcoves and pipe boxings. Diagonal work in particular generates a cut on almost every perimeter tile.
- 15% or more — large-format tiles such as 60x120 or 120x120. Each cut wastes a bigger piece, so the same number of cuts costs you more material.
- Patterned or veined tiles — if the pattern needs to line up across the floor, allow extra again, since not every tile can go anywhere.
Our calculator offers a 10% allowance as standard. It's the right figure for most jobs, but a tiler working a complicated bathroom will often want more.
Step 3: Convert to Boxes
Tiles are sold by the box, not individually, and coverage varies by format. Work out how many square metres a box covers, divide your total by that, and round up.
For example, a 60x120 tile covers 0.72m², and boxes of that format typically hold two tiles — so roughly 1.44m² per box. A 14.7m² floor plus 10% is 16.2m², which is 11.25 boxes, so you'd order 12.
Coverage differs between ranges, so always check the figure on the product page rather than assuming.
Order It All at Once
This matters more than most people expect. Tiles are produced in batches, and shade varies slightly between them. If you run short and reorder later, the new boxes may come from a different batch and the difference can be visible on a finished floor.
Work out the full quantity, add your wastage, and buy it in one go. It's also worth keeping two or three spare tiles after the job for repairs — a cracked tile in five years' time is far easier to replace from your own spares than from stock that has moved on.
Comparing Prices: m², yd² and Per Box
Tile prices in Ireland are quoted in three different ways, and the same tile can look like three different prices depending on which is used, which can make it difficult to clearly compare quotations
- Per box — what you actually pay at the till.
- Per square metre (m²) — the box price divided by the metre coverage of the box.
- Per square yard (yd²) — the same tile priced against a smaller unit, so that the price seems lower, even when it's not. A square yard is only 0.836m², so a yd² price always appears to be about 20% lower than the m² price for the identical tile, because it is covering a smaller area.
To compare like with like, multiply a yd² price by 1.2 to get the approximate m² price. A tile at €25.85/yd² is €30.90/m² — the same tile, the same money, two different-looking numbers.
We show both figures on our tile listings so you can compare against whichever unit you've been quoted elsewhere.
Use the Calculator on Any Tile Page
Rather than doing this by hand, every tile on this site has a calculator built into the product page. It works three ways: enter the number of boxes you want, enter an area in square metres, or enter wall and floor dimensions and let it work out the area for you. It handles up to six walls and offers the 10% wastage allowance.
Browse the full tile range and the calculator is on every product page.
Don't Forget the Rest
Once you know your tile quantity, the materials follow from it:
- Tile adhesive — coverage depends on trowel notch size and how flat the substrate is
- Grout — usage rises with joint width and tile format
- Spacers and levelling clips — roughly four per tile for clips, more for large format
- Tile cutters and cutting discs sized for your tile format
If you're unsure, bring your measurements into the showroom and we'll work through the whole list with you.
Frequently Asked Questions
How much extra tile should I order?
10% over the measured area for a straightforward room laid straight. 15% for diagonal or herringbone layouts, large-format tiles, or rooms with several corners and boxings.
How do I work out wall tile quantities?
Measure each wall's width by its height, add the results together, then add your wastage allowance. Only deduct openings bigger than about 1m².
Should I subtract for windows and doors?
Only for large openings. Small ones generate offcuts you can't reuse, so the material is needed anyway.
How many tiles are in a box?
It depends on the format — a 60x120 box typically holds two tiles, smaller formats hold more. The coverage per box is listed on each product page.
Why is a price per square yard lower than per square metre?
Because a square yard is smaller — 0.836m². Multiply a yd² price by about 1.2 to compare it with an m² price.
Can I order more tiles later if I run short?
You can, but shade varies between production batches, so late additions may not match. Order the full quantity at once.
Do you deliver tiles across Ireland?
Yes, to all 32 counties. See our shipping page, or collect from our Mallow showroom.
Still Not Sure?
Bring your measurements, or a rough plan, into the showroom and we'll work out quantities with you — tiles, adhesive, grout and trims. Unit 2, Majestic Business Park, Mallow, Co. Cork, or ring +353 22 53633.