Trades
Estimate floor or wall tiles from area, tile size, grout gap, waste allowance and box size.
Calculator
Effective tile module area = ((tile length + grout joint) ÷ 1000) × ((tile width + grout joint) ÷ 1000). Base tiles = area ÷ module area. Tiles with waste = ceil(base tiles × (1 + waste percent ÷ 100)). Boxes = ceil(tiles with waste ÷ tiles per box).
This is the method behind the answer, so the result can be checked rather than simply trusted.What-if check
Same measured area and tile size, with different waste allowances. This makes the order quantity easier to discuss with a supplier or tiler before buying full boxes.
| Waste | Tiles to order | Boxes / spare tiles |
|---|---|---|
| 5.0% | 69 | 9 boxes · 3 spare |
| 10.0% | 73 | 10 boxes · 7 spare |
| 15.0% | 76 | 10 boxes · 4 spare |
| 20.0% | 79 | 10 boxes · 1 spare |
Visual proof
12.00 m² ÷ 0.1827 m² per module = 65.68 base tiles. Current order: 73 tiles, rounded to 10 boxes.
Result: 73 tiles · 10 boxes. Assumption: Area is entered in square metres and tile dimensions are entered in millimetres.
Effective tile module area = ((tile length + grout joint) ÷ 1000) × ((tile width + grout joint) ÷ 1000). Base tiles = area ÷ module area. Tiles with waste = ceil(base tiles × (1 + waste percent ÷ 100)). Boxes = ceil(tiles with waste ÷ tiles per box).
For a 12 m² area and 600 × 300 mm tiles with a 3 mm grout joint, the module is 0.603 × 0.303 = 0.182709 m². Base tiles = 12 ÷ 0.182709 = 65.68. Add 10% waste and round up: ceil(72.25) = 73 tiles. With 8 tiles per box, ceil(73 ÷ 8) = 10 boxes.
Master’s Tip: sketch the first row and last row before ordering. A neat area calculation can still leave awkward slivers at walls, extra waste on diagonals, or a need for spare matching tiles from the same batch.
Standard or basis: transparent metric area arithmetic using tile dimensions, grout-joint layout allowance, user-selected waste and upward rounding. This page does not certify substrate preparation, waterproofing, slip rating, grout selection or installation compliance.
Methodology & Accuracy
CalculationTime pages are built around visible arithmetic: the formula, assumptions, worked example and practical limitations are shown so the result can be checked rather than simply trusted.
Effective tile module area = ((tile length + grout joint) ÷ 1000) × ((tile width + grout joint) ÷ 1000). Base tiles = area ÷ module area. Tiles with waste = ceil(base tiles × (1 + waste percent ÷ 100)). Boxes = ceil(tiles with waste ÷ tiles per box).
Standard or basis: transparent metric area arithmetic using tile dimensions, grout-joint layout allowance, user-selected waste and upward rounding. This page does not certify substrate preparation, waterproofing, slip rating, grout selection or installation compliance.
Where a calculator follows a named legal, trade or industry standard, that standard is cited visibly. Otherwise the page uses transparent general arithmetic and states its limits.Master’s Tip: sketch the first row and last row before ordering. A neat area calculation can still leave awkward slivers at walls, extra waste on diagonals, or a need for spare matching tiles from the same batch.
Divide the tiled area by the effective area of one tile module, add a waste percentage for cuts and breakage, then round up to a whole tile count.
For layout planning, a small grout-joint allowance can be included in the module size. It should not be confused with a full grout-volume estimate.
A common planning range is 10% for simple layouts, with more for diagonal patterns, small rooms, many corners or pattern matching. Use the waste input to test the effect.
Tiles and boxes are discrete items. If the arithmetic says 72.25 tiles or 9.13 boxes, the practical order must round up.
No. It is a transparent quantity estimate. Confirm tile batch, layout, substrate, waterproofing, trims and wastage with the supplier or installer before ordering.
Tile estimating is area arithmetic with practical ordering rules layered on top. The calculator makes the module size, grout allowance, waste percentage and box rounding visible so a homeowner, teacher, tiler or quote writer can file the numbers and check them later.
A tile laid with a grout joint occupies a repeated module on the surface. For quantity planning, adding the grout joint to the tile length and width gives an approximate coverage module before waste and box rounding are applied.
Simple rectangular rooms may need modest cutting allowance. Diagonal layouts, herringbone patterns, niches, columns, many doorways and matching grain or pattern can use more tile than the clean area suggests.
The final shopping quantity is normally rounded to full boxes. Keeping the box count and spare tiles visible helps avoid a second purchase from a different batch, where shade or calibre can vary.