Tile and ceramic calculator
Enter the area to be tiled, the tile size and how the tiles will be laid. The tool adds the right wastage for cuts at the walls, then converts the area into tiles and whole boxes, because tiles are not sold by the piece. The price is an editable default; the formula is not.
The floor or wall area to be tiled. If you do not know it, work it out on the room area calculator first.
Printed on the box and different between factories. Change it to match what you are buying.
A diagonal lay wastes more, because every tile around the edge is cut twice.
Default price from the Saudi Arabia market — checked August 2026 — change it to the quote you were given.
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Boxes needed
15 boxes
60 tiles, covering 21.6 m²
Breakdown
| Area to tile | 20m² |
| Wastage | + 7% |
| Area including wastage | 21.4m² |
| Area of one tile | 0.36m² |
| Coverage per box | 1.44m² |
| Tiles needed | 60 |
| What the boxes actually cover | 21.6m² |
| Spare over the area | 1.6m² |
| Tile adhesive | 100kg |
| Grout | 10kg |
| Estimated cost | 1,188.00 |
The cost is for whole boxes rather than for the area laid, because that is what you actually pay. Adhesive and grout quantities are rough and move with how level the floor is and how wide the joints are.
How it's calculated
The tool starts from the area to be laid and adds wastage. Wastage is not padding: every tile that meets a wall gets cut, and the offcut usually goes in the skip. A straight lay wastes about 7 percent, a diagonal one about 12, because each perimeter tile is cut on two edges.
That area is then divided by the area of one tile to give a tile count, rounded up. The tiles are divided by the pieces in a box and rounded up again, because a merchant will not sell you an opened box.
Rounding twice means you buy more than you lay, and that is deliberate. The card shows what the boxes actually cover and how much is spare, and the cost is worked out on what you buy rather than on what you lay.
- Area to buy = area × (1 + wastage)
- Tiles = area to buy ÷ area of one tile, rounded up
- Boxes = tiles ÷ pieces per box, rounded up
- Wastage used is 7 percent for a straight lay and 12 for a diagonal one
- The cost is on whole boxes, because that is what the invoice says
Worked example
A 20 m² room in 600 × 600 mm tiles sold four to a box, laid straight:
- Wastage at 7 percent: 20 × 1.07 = 21.4 m² to buy
- Area of one tile: 0.6 × 0.6 = 0.36 m²
- Tiles: 21.4 ÷ 0.36 = 59.4, so 60 tiles
- Boxes: 60 ÷ 4 = 15 boxes exactly
- What they cover: 15 × 1.44 = 21.6 m²
You buy 15 boxes covering 21.6 m² for a 20 m² floor, so 1.6 m² is spare. Keep it: a fresh batch of the same tile can come back a different shade months later.
FAQ
Why buy more than the size of the room?
Two reasons. Cuts: the tiles against the walls get cut and the offcut is usually wasted. Boxes: tiles are sold by the whole box, so if you need 59 tiles and a box holds four, you buy 15 boxes and go home with 60. The spare is not all waste, it is your repair stock.
How much wastage should I allow?
Seven percent for a straight lay in a rectangular room, twelve for a diagonal or herringbone lay. Push it to 15 percent if the space has many corners and columns, or if the tiles are large format, because every damaged piece costs more. The field takes whatever figure you want.
Are the tiles per box always the same?
No. The tool starts from the usual count for each size, but it varies between factories and even between batches. The number is printed on the box itself; change the field to match what you are buying, or the box count will be wrong.
Is the adhesive quantity accurate?
It is a rough figure. The tool allows about 5 kg per square metre at a 6 mm notch on a level floor. An uneven floor needs a thicker bed, and large-format tiles need back-buttering as well, and both push the figure up noticeably. Ask your adhesive supplier for the coverage of the specific product.
Does this work for walls?
Yes, just enter the wall area instead. Bear in mind that wall tiles are usually a smaller format and thinner, and that wastage tends to run a little higher because of openings and cutting around services.
Related tools
Sources
✓ Reviewed September 2026- Wastage of 7 percent for a straight lay and 12 percent for a diagonal one, the figures the trade works to for cuts at walls and corners
- Pieces per box for each size are the counts these formats are usually sold in, landing between roughly one and two square metres a box, and the field is editable
- Adhesive at about 5 kg per square metre at a 6 mm notch on a level substrate, and grout at about 0.5 kg per square metre for 600 × 600 tiles at a 3 mm joint
- The default price is dated in the pricing config and shown as an editable field, because it is the only number on this page that goes out of date
Assumptions used
- Cuts at walls and corners. A straight lay wastes about 7 percent; a diagonal or herringbone lay wastes about 12 because every perimeter tile is cut twice.
- Pieces per box are the counts these formats are usually sold in, which land near 1.0-1.9 m2 a box. Box counts vary by brand, so the field is editable.
- Cement-based adhesive at a 6 mm notch. Thicker beds on uneven floors, or large-format tiles needing back-buttering, use more.
- Rough allowance for 600x600 tiles at a 3 mm joint. Smaller tiles have more joint per square metre and use more grout.