Tile Calculator
Measure once, order once — never mid-job.
Work out how many tiles you need for any floor or wall in metric. Enter your room size and tile size and the calculator gives you the tile count with the grout gap and a waste allowance built in, plus optional boxes and cost.
Estimates from room and tile geometry — confirm the exact coverage on your tile's box or spec sheet.
How the tile count is worked out
Area ÷ tile footprint, then add waste
The calculator takes the area you're tiling (room length × width, plus any extra area) and divides it by the footprint of a single tile. The footprint is the tile size plus the grout gap on each side, because every tile carries a share of the surrounding grout line — so a 300 × 300 mm tile with a 3 mm gap effectively occupies about 303 × 303 mm. It then adds a waste allowance for the offcuts and breakage that every job produces.
Worked example
A 20 m² floor in 300 × 300 mm tiles with a 3 mm grout gap needs about 218 tiles to cover the area (roughly 10.9 tiles per m²). Add the standard 10% straight-lay waste and you're at about 240 tiles — the number to actually order. Big tiles cover ground faster: the same maths puts 600 × 600 mm tiles at only ~2.75 per m², so a 15 m² area needs about 46.
How much extra to buy for waste
Waste covers the offcuts you can't reuse and the occasional cracked tile. As a rule of thumb:
- 10% — a standard straight (grid) lay.
- 15% — diagonal or herringbone patterns, which produce more cut edges.
- 15–20% — rooms with lots of cuts: many corners, niches, a curved wall, or large-format tiles that are costly to mis-cut.
Order the whole job in one go so every tile shares the same dye lot (batch) — colour and size drift slightly between production runs, and a top-up box bought later rarely matches. It's always cheaper to over-order by one box than to run out mid-job. Keep one or two spare tiles afterwards for future repairs.
Walls, splashbacks and odd-shaped rooms
Wall tiling uses the same maths — just swap the floor area for the wall area. For a single wall or splashback, use height × width (for a splashback, that's the height of the tiled band × the length of the bench). Enter that as your room dimensions, or add it through the extra-area field.
For a full bathroom, work out each wall separately and add them together. Subtract large openings — a window, a mirror recess, a doorway — by reducing the area you enter; there's no need to fuss over small penetrations like a tap or power point, as the waste allowance absorbs them. Wall tiles are usually thinner and lighter than floor tiles, but the counting is identical.
Boxes, cost and the extras beyond the tiles
Boxes
Tiles are sold by the box, and the tiles-per-box varies with size and brand — a box of 600 × 600 might hold 3–4, a box of 300 × 300 around 9–13. Enter the tiles-per-box from the product page and the calculator rounds your total up to whole boxes, which is what you'll actually pay for.
Cost and extras
Enter a price per box for a rough tile spend, but remember tiles are only part of the job. Budget separately for adhesive (a 20 kg bag covers roughly 4–5 m²), grout, spacers, waterproofing (compulsory in wet areas), edge trims, and either hire gear or a tiler's day rate. As a rough, approximate guide, many Australian floor-tiling jobs land somewhere around $45–$100 per m² supplied and laid, depending heavily on the tile and the amount of prep — treat that as a ballpark, not a quote. Note that 'rectified' tiles are cut to size after firing, so a nominal '600' tile is often about 597 mm actual.
❓ Frequently asked Frequently asked questions
How many tiles do I need?
Divide the area you're tiling by the footprint of one tile — where the footprint is the tile size plus the grout gap on each side — then add a waste allowance for cuts and breakage. A 20 m² floor in 300 × 300 mm tiles works out to roughly 218 tiles to cover the area, or about 240 once you add 10% for waste. Buy in whole boxes.
How much extra should I add for waste?
Add about 10% for a standard straight (grid) lay, 15% for diagonal or herringbone patterns, and up to 20% for rooms with lots of cuts — many corners, niches or a curved wall. Waste covers offcuts you can't reuse and the odd cracked tile. It's always cheaper to over-order by one box than to run out mid-job and chase a dye-lot match.
Does the grout gap change the number?
Yes, slightly. Each tile plus its grout gap covers a little more than the bare tile, so a wider gap means marginally fewer tiles. On 300 × 300 tiles the difference between a 1.5 mm and 3 mm gap is only a few tiles across a room; on large-format tiles with 4–5 mm gaps it adds up. The calculator factors the gap into the coverage automatically.
How do I work out boxes?
Tiles are sold by the box, and the tiles-per-box varies with size and brand — a box of 600 × 600 might hold 3–4, a box of 300 × 300 around 9–13. Enter the tiles-per-box from the product page and the calculator rounds your total up to whole boxes, which is what you'll actually buy.
Can I use it for wall tiles?
Yes. For a wall or splashback, use the wall's height × width as the area instead of the floor. Subtract large openings like a window or mirror recess, and add each wall together for a full room. The counting maths is identical — wall tiles are just usually thinner and lighter than floor tiles.
Does it include adhesive and grout?
No — it estimates tile quantity and, optionally, the tile cost. Budget separately for adhesive (a 20 kg bag covers roughly 4–5 m²), grout, spacers, waterproofing in wet areas, edge trims, and either hire gear or a tiler's day rate.
Where these figures come from
This is a geometry-based estimate — the tile count comes from your room and tile dimensions, not from any external rate table. The guidance below reflects standard trade practice.
- Australian tiling practice — wall and floor tiling in Australia is carried out to AS 3958 (ceramic tiles), and waterproofing of wet areas is a separate compulsory requirement.
- Waste allowances — 10% straight-lay, 15% diagonal/herringbone, and up to 20% for heavily cut rooms are widely used industry rules of thumb, not a fixed standard.
- Coverage and boxes — verify the exact tile size, tiles-per-box and m²-per-box on the product's box or spec sheet; 'rectified' sizes differ slightly from the nominal size.
Last checked: July 2026. Cost ranges are approximate and vary by tile, region and site — always get a written quote from your tiler or supplier.
Select the question that matches where you are right now.
The headline number is how many tiles to buy: enough to cover the area plus a waste allowance for cuts and breakage. If you entered a tiles-per-box figure, it's rounded up to whole boxes — the amount you'll actually carry home.
Take the tile count (or box count) to the supplier and buy it all in one purchase so every tile shares a dye lot. Keep one or two spares for future repairs.
It's not a full materials list. Adhesive, grout, waterproofing, trims and labour are separate — the optional cost figure only covers the tiles themselves.
The coverage maths (area ÷ tile-plus-gap footprint) is exact; real jobs vary with layout and cutting, which is what the waste allowance absorbs. Confirm coverage on the tile's box.
Four things move the tile count: the area, the tile size, the grout gap, and the waste allowance.
Bigger tiles cover far more per unit: about 10.9 tiles/m² for 300 × 300 versus ~2.75/m² for 600 × 600. But large formats need a flatter substrate and more careful cutting.
Each tile plus its gap covers slightly more than the bare tile, so a wider gap means marginally fewer tiles — small on mosaics, more noticeable on large formats with 4–5 mm gaps.
10% for a straight lay, 15% for diagonal or herringbone, up to 20% for heavily cut rooms. It's the difference between finishing the job and chasing a discontinued batch.
A few habits stop you over- or under-ordering.
Measure each wall or floor at more than one point — rooms are rarely perfectly square. Use the largest dimension and let the waste allowance cover the taper.
Order the whole quantity at once so colours and sizes match. Confirm whether the price is per tile, per box or per m² before you compare offers.
Bump the allowance up for diagonal, herringbone or a room full of cuts; keep it at 10% for a simple grid on a square room.
Tiling is usually one line in a bigger renovation budget. Model the money side too.
See what monthly repayments a renovation adds to your home loan.
Mortgage repayments →Check your borrowing capacity before you commit to a bigger job.
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