Tile Calculator
Find out how many tiles you need for a floor or wall
How many tiles do I need?
The tile calculator turns the area you are tiling into a tile count. Divide the surface area by the area one tile covers, then add a waste factor for the pieces you will cut, drop, or set aside for repairs. The two details people miss are the grout line — which makes each tile cover a little more than its bare size — and buying enough spare tiles from the same batch.
Measure the floor or wall in feet and multiply to get square feet. A 3.05 × 3.05 m floor is 9.3 m². A tile about 30 cm with a 1/8-inch grout line actually occupies about 12.125 × 12.125 inches, or 0.1 m², so 9.3 m² needs roughly 98 bare tiles — then you add waste on top.
Choosing a waste factor
- 5% — a large, simple rectangle with straight edges and few obstacles. The minimum worth ordering.
- 10% — the standard for a normal grid layout in a typical room, allowing for perimeter cuts and the odd breakage.
- 15% or more — diagonal, herringbone, or brick-offset patterns, small or oddly shaped rooms, and large-format tiles, all of which create more cut waste.
Grout and mortar
The calculator also estimates the grout (filler for the joints) and thin-set mortar (the cement-based adhesive under the tile) you'll need, rounded up to whole bags. Grout is sold by the pound and mortar by the 50 lb bag — both estimates depend on your tile size, joint width, and thickness, and real coverage varies by brand and trowel, so treat them as a shopping-list starting point and check the bag's coverage chart before the final order.
Frequently asked questions
Why add a waste factor at all? Almost every job needs cut tiles at the edges, and some tiles crack during cutting or setting. The waste factor makes sure you have full tiles to cut from, plus a few spares for the future.
Does the grout gap really change the count? A little. A wider grout line means each tile plus its grout covers more area, so you need marginally fewer tiles. On small tiles with wide grout the effect adds up, which is why the calculator accounts for it rather than assuming a bare tile size.
Should I buy by the tile or by the box? Tile is sold by the box, and each box states its square-foot coverage. Take the total tiles (or total square feet plus waste) and round up to whole boxes — and keep at least a few leftover tiles from the same lot for repairs.
What about walls versus floors? The math is identical — length × width of the surface. Wall tile tends to have fewer cuts than a floor with cabinets and fixtures to work around, so a lower waste factor is often fine.
How accurate are the grout and mortar estimates? They're a starting point, not a guarantee. Grout usage scales with joint width and tile thickness; mortar coverage depends on the trowel notch size, which the installer picks for the tile — both vary by manufacturer. Round up, and keep the receipt in case you need a bit more or can return an unopened bag.
These are planning estimates. Confirm the box coverage and dye lot at purchase, and see our tiling and decorating guides for layout and setting technique.