Tile calculator

How the tile count is calculated

tile area = (width + grout) × (height + grout) ÷ 10,000 · area with waste = area × (1 + waste ÷ 100) · tiles = area ÷ tile area (rounded up) · boxes = tiles ÷ tiles per box (rounded up)

First the calculator works out how many square meters one laid tile takes up. The format is entered in centimeters, so width and height are multiplied and divided by 10,000 to get square meters. If you also enter a grout width, it is added to both sides, because a laid tile occupies its own size plus one joint.

The area you are tiling is then divided by that figure and rounded up — you cannot buy half a tile. If you need the floor or wall area first, work it out in the area calculator and enter it here in the “I know the area” mode.

Finally the same sum is repeated on the area increased by the waste, and that number is divided by the tiles per box and rounded up again. That is why the result shows two figures: how many tiles cover the surface itself, and how many you actually buy once everything comes in full boxes.

How to measure and what gets deducted

For a floor, enter the length and width of the room. For walls, enter the length, the width and the height the tiles reach — often not the full room height but, say, 1.2 m behind a sink. If you are tiling a narrow strip lower than half a meter, switch to the “I know the area” mode and enter the square meters directly.

In wall mode the openings (doors and windows) are deducted, while in floor mode the deductions are everything that stays untiled: a bathtub, a shower tray, kitchen cabinets, a shower enclosure or a recess. Each deduction has a width, a height and a quantity, and is subtracted at its full area.

Full area means the calculator does not assume you will reuse the offcut from around the bath somewhere else. That is deliberately conservative: small offcuts rarely fit anywhere in practice, and it is better to be left with a few tiles than to be short half a row.

If you are tiling several identical rooms, enter the measurements of one and how many there are — deductions are entered per room and multiplied by the same number.

Waste: straight, diagonal and patterned

Waste covers cutting at the edges, breakage in transport and during laying, and tiles rejected for shade. The calculator starts at 10%, and the buttons above the field only prefill that same field — the value stays yours to change.

Straight laying is usually planned at 10%, diagonal at 15%, and a more involved pattern (herringbone, offset brick, mixed formats) at 20%. Diagonal needs more because every edge is cut at an angle, and the piece left over is rarely usable again.

These are planning conventions, not a standard or a regulation. In a small room with many corners use more; on a large, regular floor with a good tiler you can use less. The waste is added to the area before the tiles and boxes are calculated.

Worked example: a 2.4 × 1.8 m bathroom

A 2.4 × 1.8 m bathroom floor is 4.32 m². With a 30 × 60 cm tile and a 3 mm joint, one laid tile takes up (30.3 × 60.3) ÷ 10,000 = 0.182709 m². For the surface alone that is 4.32 ÷ 0.182709 = 23.64, so 24 tiles.

With 10% waste the area is 4.752 m², which comes to 27 tiles. If a box holds 8 pieces you need 4 boxes, that is 32 tiles — 8 are left over as spares. If a box costs 28 KM the material comes to 112 KM; prices differ by supplier, so enter your own.

The same room with no grout: the tile takes up exactly 0.18 m², so the raw count is 4.32 ÷ 0.18 = 24.00. The joint moved the figure from 24 to 23.64, but the number of boxes stayed the same — 4. That is a pattern worth remembering: grout changes the raw count and rarely changes how many boxes you carry home.

Adhesive and grout mass are deliberately not estimated here. Consumption is printed on the bag and depends on the trowel notch, how flat the substrate is and the tile format, so any figure we quoted would be guesswork. Take the number from the label of the product you are buying and multiply it by your own square meters.