Tile Calculator
Written by Thierno Sadou Diallo, formula verified per our methodology • Last checked on 9/5/2026
The number of tiles needed is calculated by dividing the room's area (with a margin for waste) by the area of one tile. For a 4 × 3 m room with 60 × 60 cm tiles and a 10% margin, you'll need 37 tiles.
Explanation
This calculator estimates the number of tiles to buy for tiling a rectangular room: it multiplies the room's area by a waste margin (to allow for cuts around walls and doors, and broken tiles), then divides that total by the area of one tile, always rounding up to the next whole tile (you can't buy a fraction of a tile, and it's better to have a little extra than to run short mid-job). The recommended waste margin depends on the laying pattern: about 10% for a simple straight layout, more (15 to 20%) for a diagonal or complex pattern layout, which generates more cuts. This calculator assumes a simple rectangular room, without subtracting the area of fixed fixtures (a kitchen island, a bathtub...): for an irregularly shaped room, break it down into several rectangles and add up the results. For the amount of paint needed on the walls of the same room, see our paint quantity calculator.
Example: a 4 × 3 m room, 60 × 60 cm tiles
Inputs
Room: 4 m × 3 m. Tile: 60 cm × 60 cm. Waste margin: 10%.
Calculation
Room area = 4 × 3 = 12 m². With a 10% margin: 12 × 1.10 = 13.2 m². Area of one tile = 0.6 × 0.6 = 0.36 m². Number of tiles = 13.2 ÷ 0.36 = 36.67, rounded up to 37.
Result
You'll need 37 tiles of 60 × 60 cm for this room.
Frequently asked questions
Why plan for a waste margin instead of the exact number?
Because tiling a room almost always involves edge cuts (near walls, in corners, around doors), which produce unusable offcuts. Without a margin, the exact calculation almost always falls short in practice, forcing you to order a second delivery that may differ slightly in shade (a different manufacturing batch).
What margin should I use for a diagonal layout?
A diagonal layout (tiles at 45°) generates more edge cuts than a classic straight layout: plan for 15 to 20% margin instead of the usual 10%. A checkerboard pattern or a complex layout with multiple tile sizes calls for a similar margin, or even higher.
Does this calculator account for grout lines between tiles?
No, this calculator uses the tile dimensions directly, without adding the space taken up by grout lines. For standard tiling, grout line thickness stays thin enough not to significantly change the number of tiles needed, but it does affect the amount of thin-set mortar and grout to plan for separately.