Tile Calculator
Dividing the floor area by the area of one tile is the standard way to estimate tiles, and it is the reason people run short: a tile cannot be cut up and reassembled across the room, so the count has to round up once per row and once per column, not once over the whole floor. This lays the tiles out both ways — the naive area figure and the honest row-by-row figure — shows the gap between them, adds the grout joint into the tile footprint, applies your waste allowance, and rounds the boxes up to what a shop will actually sell you.
- Accurate
- Real-time
- Easy to use
- 100% free
Tiles needed
53 tiles
Total tile cost
$630.00
Details
Updates as you typeRooms are measured in metres or feet, tiles in centimetres or inches, and the grout joint in millimetres or inches.
The wall-to-wall run the tiles are laid along. For a wall rather than a floor, this is the wall width.
The other run, across the tiles. For a wall, this is the height being tiled.
The tile side that runs along the room length. Swapping the two tile sides can change the total, so it is worth trying it both ways.
The tile side that runs across the room width.
The gap between tiles. 2-3 mm (about 1/8 in) for rectified porcelain, 3-5 mm for ceramic, more for stone. Set it to zero for a butt joint.
10% is the usual trade allowance for cuts and breakages. Allow 15% for a diagonal or herringbone lay, or a room with many corners.
Printed on the box. Large-format 60 x 60 cm porcelain is usually 4 to a box; 30 x 30 cm ceramic is often 10 or more.
What one box of the tiles above costs. Leave it at zero if you only want the counts.
Summary
A real gap — 6% to 12% more than the area figureTiles needed
53 tiles
Tiles purchased
56 tiles
- Uncut tiles35 tiles63%
- Cut at the edges13 tiles23%
- Waste allowance5 tiles9%
- Spare in the last box3 tiles5%
- Boxes to buy
- 14 boxes
- Total tile cost
- $630.00
- Tiles by layout (rows × columns)
- 48 tiles
- Tiles by area (the naive figure)
- 44 tiles
- Tiles the area method misses
- 4 tiles
- Floor area
- 15.75 m²
- Laid out row by row this floor takes 48 tiles. Dividing the area by one tile's footprint gives 44, because that division quietly assumes every offcut can be reused somewhere else in the room. The gap between the two figures is 4 tiles before any allowance for breakage.
- The true requirement sits between the two: the area figure assumes perfect offcut reuse, the layout figure assumes none at all. The order here is built on the layout figure, because being over is a leftover box and being under is a second delivery from a different batch.
- Tile batches vary in shade. Buy the whole job in one order, keep the spares, and check the batch number on every box before the first one is opened.
- For a rectangular tile the orientation matters — swapping the tile length and width can change the total by a whole row. Try it both ways and take the smaller answer.
- Boxes are rounded up, never averaged: a job needing 13.25 boxes takes 14. That is why the cost climbs in steps rather than smoothly as the room grows.
- Those 48 tiles present 17.28 m² of tile face on a 15.75 m² floor. The difference between the two is the grout joints plus everything trimmed off at the walls.
How this is calculated
- Room
- 4.5 × 3.5 m
- Floor area = length × width
- 15.750 m²
- Tile
- 60 × 60 cm
- Grout joint
- 3.00 mm
- Tile footprint = (tile + joint) each way
- 0.36361 m²
- Area method: floor area ÷ footprint
- 43.316 tiles
- Area method, rounded up
- 44 tiles
- Tiles along the length = (4.5 + joint) ÷ 0.6030 m
- 7.468 tiles
- Rounded up to whole rows
- 8 rows
- Tiles across the width = (3.5 + joint) ÷ 0.6030 m
- 5.809 tiles
- Rounded up to whole columns
- 6 columns
- Layout method = rows × columns
- 48 tiles
- Difference: tiles the area method misses
- 4 tiles
- Uncut tiles in the field
- 35 tiles
- Tiles that need cutting
- 13 tiles
- Waste allowance
- 10%
- Tiles needed = layout + allowance, rounded UP
- 53 tiles
- The area method would have ordered
- 49 tiles
- Tiles per box
- 4 tiles
- Boxes needed exactly = tiles ÷ tiles per box
- 13.250 boxes
- Boxes to buy = rounded UP to a whole box
- 14 boxes
- Tiles purchased = boxes × tiles per box
- 56 tiles
- Spare tiles in the last box
- 3 tiles
- Price per box
- $45.00
- Total cost = boxes × price
- $630.00
Waste allowance (%)
Compare scenarios
See how one change moves the result
- CurrentYour inputs as they stand53 tilesCurrent
- Room lengthm 5.666 tiles
- Room widthm 4.471 tiles
- Tile lengthcm 7540 tiles
Frequently asked questions
Why does area divided by tile area come out too low?
Because that division assumes a tile can be cut into pieces and every offcut reused somewhere else in the room, which is not how tiling works. A run of floor 4.5 m long takes eight 60 cm tiles, not 7.47 of them, and the same rounding happens again across the width. Round up once per row and once per column and a 4.5 by 3.5 m floor comes to 6 x 8 = 48 tiles, against 44 by area — four tiles short before anything has been broken or mis-cut.
How much waste should I allow?
10% is the usual trade allowance for a straight lay in a simple rectangular room, and it is what this starts with. Go to 15% for a diagonal or herringbone pattern, where almost every perimeter tile is a cut, or for a room with lots of alcoves, doorways and pipe boxings. Large-format tiles also justify more, because a single mis-cut wastes a bigger piece. The allowance is on top of the layout count, and it covers breakage in transit, mistakes on the day, and a few spares to keep for repairs.
Should the grout joint be included?
Yes, and this includes it in both figures. A tile occupies its own face plus one joint in each direction, so 60 cm tiles at a 3 mm joint sit on a 60.3 cm pitch. Eight of them along a 4.5 m run have seven joints between them, which is 21 mm of grout — not enough to change this particular answer, but enough to matter with small mosaic tiles where the joint can be a tenth of the tile itself.
Which number should I actually order from?
The layout figure plus your waste allowance, which is the headline here. The area figure assumes perfect offcut reuse and the layout figure assumes none at all, so the truth is between them — but the two errors are not symmetrical. Ordering over leaves you with a spare box, which is worth having anyway for future repairs. Ordering under means a second delivery, days lost, and tiles from a different batch that may not match the shade of the first.
Does it matter which way round the tile goes?
For a square tile, no. For a rectangular one it can change the total by a whole row, because the rounding up happens against different room dimensions. A 30 x 60 cm tile in a 4.5 by 3.5 m room comes out differently with the long side running along the room than across it. Swap the tile length and width here and take the smaller answer — then check the pattern still looks right, since plank-format tiles are usually laid with the long side along the longest sightline.
Why round boxes up?
Because shops sell boxes, not tiles. If the maths says 13.25 boxes you buy 14, and you pay for all 14 — the three spare tiles are on the receipt whether you use them or not. Rounding to the nearest box instead would leave a job three tiles short, which means a second trip and possibly a second batch. The spare tiles are shown separately here so you can see what the box size is costing you; a smaller box size sometimes costs less overall even at a higher price per tile.
Does this work for walls as well as floors?
Yes — a wall is the same grid problem. Enter the wall width as the room length and the tiled height as the room width, and the layout works out identically. Deduct nothing for a window or a door opening unless it is large: the tiles cut around a small opening are rarely reusable, so the full-rectangle count is usually closer to what you need than a deducted one.