Calculate tiles, boxes, waste, grout and cost for floors, walls, bathrooms, showers and splashbacks — with the tile module worked and shown.
Tile Size
Joint depth is usually close to the tile thickness — check your tile’s data sheet for an exact figure.
Grout & Adhesive (optional)
Set automatically from tile size (trowel notch) — override if your installer specifies a different notch.
Cost
| Item | Value |
|---|
In Australia, tiles are measured and sold in m². Common residential tile sizes are 300×300mm, 400×400mm, 600×600mm, 600×300mm (plank), and 800×800mm. Large format tiles (600×600mm+) are popular in modern Australian homes.
Always add at least 10% wastage for cuts, breakage, and future repairs. Diagonal layouts require 15% extra. Order all tiles from the same batch number to ensure colour consistency. Grout joint width affects the finished look — rectified tiles can use 2mm joints; natural edge tiles typically need 5mm+.
Written and reviewed by Mohsin Iqbal · Last reviewed August 2026
A tile calculator works out how many tiles, boxes and how much material you need to cover an area — not just the raw area itself. If you need the area on its own first (for a quote, or before you've chosen a tile), the Square Footage Calculator or the Area Calculator handle that separately. Tiles come in fixed sizes and are packed in fixed box quantities, so the real-world number you need to buy is always rounded up from the pure geometry, and grout joints, layout pattern and waste allowance all push that number higher again.
The method has four steps, in order:
Net area = Gross area − openings
Tile module = (Tile length + grout gap) × (Tile width + grout gap)
Base tiles = ceil(Net area ÷ Module area)
Total tiles = ceil(Base tiles × (1 + (waste% + pattern%) ÷ 100))
Boxes = ceil(Total tiles ÷ tiles per box)
Floors are the simplest case: gross area is just length times width, with no wall height or openings to think about. A 4m × 3m floor is a 12m² gross area — whatever the tile size and grout joint, that 12m² is the starting figure everything else builds from.
Walls need one extra step: gross wall area is width times height (not length times width), and doors or windows are subtracted before the tile count is worked out. A wall doesn't stop being "wall" because a window interrupts it — you're just not tiling that section.
Bathrooms usually combine a floor calculation and one or more wall calculations, run separately and added together, since floor and wall tiles are frequently different sizes and sometimes different products entirely. Run each area through the calculator on its own settings rather than trying to average them into one combined figure.
A shower recess with three tiled walls is really three separate wall calculations — typically two side walls of the same width and one back wall, each run through with its own height and opening deductions (a shower usually has no door opening cut into the tiled wall itself, since the screen sits in front of it). Add the three net areas together, then calculate tiles once on the combined total, since running waste and box rounding on each wall separately would over-order.
Tiling directly onto a slab? The Concrete Calculator works out the slab volume before this page takes over for the tile quantity. A splashback is a wall calculation with a short height and, often, no waste-worthy openings at all — power points are usually cut around rather than treated as full opening deductions, since they're small relative to a whole tile. Height is typically 600–900mm between benchtop and upper cabinets or extraction; measure the actual gap on site rather than assuming a standard figure.
| Size | Common use |
|---|---|
| 100mm × 100mm | Mosaic, feature strips |
| 300mm × 300mm | Bathroom floors, older-style walls |
| 300mm × 600mm | Splashbacks, subway-style layouts |
| 600mm × 600mm | Living areas, modern bathroom floors |
| 600mm × 1200mm and larger | Large-format living and outdoor areas |
The grout gap isn't wasted space — it's a functional joint that allows for tile expansion and gives the surface a flat, even finish over a substrate that's never perfectly true. This calculator treats the gap as adding to each tile's effective footprint (the module), which is the standard way tiling calculators estimate quantity — but real perimeter cuts and edge conditions aren't captured by a module estimate alone, which is exactly what the separate waste allowance exists to cover.
| Application | Typical grout gap |
|---|---|
| Rectified large-format tiles | 1.5–3mm |
| Standard floor tiles | 2–4mm |
| Natural stone, handmade tiles | 4–8mm |
| Mosaic sheets | Usually fixed by the sheet, 2–4mm |
Waste covers cutting losses at the perimeter, breakages, and future repairs from the same batch. 10% is the standard default for a simple rectangular room laid straight. It is not a substitute for the pattern allowance below — the two are added together, not one replacing the other.
Straight / Grid
Brick / Offset
45° Diagonal
Herringbone
| Pattern | Extra allowance (on top of base waste) |
|---|---|
| Straight / grid | 0% |
| Brick / offset (running bond) | +5% |
| Random ashlar | +10% |
| Basketweave | +10% |
| 45° diagonal | +15% |
| Herringbone | +20% |
| Versailles / French pattern | +20% |
| Chevron | +25% |
Random ashlar and basketweave stagger rectangular tiles without any angled cuts, so they sit closer to brick/offset in material demand. Versailles (French pattern) mixes four different tile sizes into one repeating module and needs a full spare kit on hand, since a single broken large tile can't be replaced from a different batch. Chevron needs a mitred (angled) cut on every single tile, which is why it carries the highest allowance of any pattern here.
Boxes are always rounded up — there's no such thing as buying 9.25 boxes. If you know the tiles-per-box figure, enter it directly. If your supplier instead quotes box coverage in square metres, divide that coverage by one tile's area to get an equivalent tiles-per-box figure for this calculator.
Tiling is usually one line item in a bigger renovation — the paint and flooring for the rest of the room are worth budgeting alongside it. Cost is calculated on the total tiles to buy (after waste and pattern allowance), not the base tile count — since that's what you actually pay for. Cost per square metre is then back-calculated against the net area, which is a useful figure for comparing tile products against each other independent of room size.
Doors and windows reduce the area you actually need to tile. The combined opening area can never exceed the gross area it's being subtracted from — if it does, something has been measured wrong. Small openings like power points and light switches are usually not worth deducting individually; the general waste allowance absorbs them.
Large-format tiles (600mm and above) need a thicker adhesive bed and a bigger trowel notch to support their weight and stay flat, which is why this calculator suggests a larger bed thickness automatically as tile size increases. They also tend to show lippage (uneven edges) more visibly than small tiles if the substrate isn't dead flat, which is a substrate-preparation issue rather than a quantity one — but it's worth budgeting extra time, not just extra tiles, for a large-format job.
Mosaic tiles are usually sold pre-mounted on sheets, commonly around 300mm × 300mm. Treat the whole sheet as a single "tile" in this calculator — enter the sheet dimensions as the tile size, set tiles per box to however many sheets come in a box (often sold loose or in packs rather than true boxes), and set grout gap to 0, since the individual mosaic pieces' spacing is already fixed by the sheet and isn't something you configure separately.
| Step | Working | Result |
|---|---|---|
| Gross / net area | 4m × 3m | 12.00 m² |
| Tile module (3mm grout) | 603mm × 303mm | 1,827.1 cm² |
| Base tiles | 12.00 ÷ 0.18271, rounded up | 66 tiles |
| +10% waste | 66 × 1.10, rounded up | 73 tiles |
| Boxes (8 per box) | 73 ÷ 8, rounded up | 10 boxes |
An 8m total wall run at 2.4m high, with a 1.6m² door opening, tiled in 300mm × 300mm with a 2mm grout joint:
| Step | Working | Result |
|---|---|---|
| Gross wall area | 8m × 2.4m | 19.20 m² |
| Net area | 19.20 − 1.60 | 17.60 m² |
| Base tiles | module 302mm × 302mm | 193 tiles |
| +10% waste | 193 × 1.10, rounded up | 213 tiles |
| Boxes (10 per box) | 213 ÷ 10, rounded up | 22 boxes |
Same room, laid on a 45° diagonal instead of straight: base waste 10% plus the diagonal's +15% pattern allowance, applied together to the base tile count, gives 98 tiles in 17 boxes of 6 — noticeably more than a straight lay of the same room would need.
A 2m × 1.5m area (3.00 m²) using 300mm × 300mm mosaic sheets, sold individually (1 per "box"), no grout gap entered since it's fixed by the sheet: 38 sheets needed, including the 10% waste allowance.
A 5m × 4m floor (20.00 m²) in 600mm × 600mm tiles, 3mm grout, 4 tiles per box: base 56 tiles, 62 with 10% waste, giving 16 boxes and 2 spare tiles left over after rounding up to a whole box count.
Tile is sold slightly differently depending on the market, though the underlying maths here works the same way regardless. Switch the Measurement unit selector above to feet or inches to work entirely in US units — every result still shows the metric figures too.
| Measure | Australia | United States |
|---|---|---|
| Tile size labelling | Millimetres (e.g. 600x600mm, 300x600mm) | Inches (e.g. 12x12in, 12x24in) |
| Area sold/quoted in | Square metres (m²) | Square feet (sq ft), sometimes m² on imported product |
| Box coverage labelling | m² per box | Usually sq ft per box — enter it directly once you switch the unit selector to feet |
| Typical install cost | $40–$100+ per m² labour, varies by tile size and pattern | $5–$14+ per sq ft labour and materials combined, varies by region and tile type |
If a US tile box states its coverage in square feet, switch the unit selector to Feet (ft) first, then enter that box-coverage figure directly into the "Box coverage" field — it now reads as ft² per box and the calculator converts everything internally, so you don't need to do any manual conversion.
Grout and adhesive coverage figures are based on published trade and manufacturer guidance for standard cement-based products; actual coverage varies by brand, substrate and site conditions. Waste allowances by pattern reflect commonly cited ranges across Australian and international tiling trade resources. Always confirm quantities and installation requirements with your tile supplier or a qualified tiler before ordering.
This calculator estimates tile quantities only. Tile layout, substrate condition, waterproofing, movement joints and installation requirements should be confirmed with a qualified tiler or the relevant product manufacturer.
Divide the net area by the tile module (tile size plus its share of the grout gap), round up, then add your pattern and waste allowance and round up again. For a 12m² room with 600×300mm tiles and a 3mm grout joint, that's 66 base tiles, rising to 73 with 10% waste.
Divide 1 square metre by the tile's area (length × width, in metres). A 600×300mm tile covers 0.18 m², so 1 ÷ 0.18 ≈ 5.6 tiles per square metre before accounting for grout gaps or waste.
10% is standard for a straight-laid rectangular room. Diagonal layouts typically need an extra 15% on top of that, and herringbone an extra 20% — the two allowances add together rather than one replacing the other.
Yes. A wider grout joint makes each tile's effective footprint (the module) larger, which reduces how many tiles fit into a given area and increases the tile count needed to cover it — the effect is small per tile but adds up across a whole room.
It varies by product — commonly anywhere from 4 to 12 tiles per box depending on tile size. Check the box or product listing for the exact figure, or use box coverage in square metres if that's what your supplier quotes instead.
Multiply wall width by wall height for the gross area, subtract any doors or windows for the net area, then run the same module/waste/box calculation used for floors.
Calculate each opening's area (width × height) and subtract the total from the gross wall area before working out tile quantity. The combined opening area can never exceed the gross wall area it's being subtracted from.
Whatever's left over after rounding up to full boxes is usually enough for minor repairs — this calculator shows that figure as "spare tiles." For long-term repair stock from a batch that might be discontinued, keeping a full spare box is a reasonable extra precaution on a job you expect to own for years.
Use the same area and tile-size inputs as a straight lay, but select the diagonal pattern option, which adds roughly 15% extra on top of your base waste allowance to account for the larger triangular offcuts a 45° layout produces at every edge.
Not necessarily more waste percentage, but they do need a thicker adhesive bed and larger trowel notch — this calculator adjusts the suggested bed thickness upward automatically as tile size increases, since a bigger tile needs more support across its larger, heavier footprint.
Treat each sheet as a single large "tile" — enter the sheet's outer dimensions as the tile size, set the grout gap to 0 since the mosaic pieces' spacing is already fixed by the sheet, and set tiles per box to however many sheets come in a pack.
Yes, always — suppliers sell whole boxes, not fractional ones, so 9.25 boxes means ordering 10. This calculator rounds up automatically and shows the leftover as "spare tiles."
It depends on the tile: rectified large-format tiles often use 1.5–3mm, standard floor tiles 2–4mm, and natural stone or handmade tiles 4–8mm to accommodate their less consistent edges. Check the tile manufacturer's recommendation for your specific product.
Yes — the underlying tile-count formula is identical. The only difference is how you calculate the gross area: length × width for a floor, width × height for a wall, with openings subtracted for walls where relevant.
Multiply the total tiles to buy (after waste and pattern allowance are applied) by the price per tile. This calculator also shows cost per square metre, calculated against the net area, which is useful for comparing different tile products on a like-for-like basis.
Switch the Measurement unit selector to Feet, then enter your room length and width in feet as normal — the calculator converts everything internally and shows the tile count, box count and area in both square feet and square metres.
Set the unit selector to Feet first — the "Box coverage" field then reads as square feet per box, so you can enter the number straight off the box without converting it to square metres yourself.