Tile Calculator

The starting calculation is straightforward — divide your room's total area by the area of a single tile — but getting a number you can actually shop with requires a few more steps that a lot of first-time buyers skip, and skipping them is exactly why people end up short by a box or two mid-installation. First, measure your room accurately: for a rectangular room, multiply length by width in the same unit (feet or metres) to get the area. For an L-shaped or irregular room, the most reliable approach is to mentally split the space into two or more rectangles, calculate each one's area separately, and add them together, rather than trying to average out an irregular shape, which tends to introduce meaningful error. Second, convert your tile's dimensions into an area in the same unit as your room measurement — a 600mm x 600mm tile is 0.6m x 0.6m, or roughly 1.968ft x 1.968ft, giving an area of about 3.87 square feet per tile. Third, and this is the step most commonly missed, add a wastage allowance before finalizing your purchase quantity, since the raw division of room area by tile area assumes every single tile is used whole with zero cuts and zero breakage, which never happens in a real installation. A straightforward rectangular room with a standard grid layout typically needs 5-8% extra; a room with more corners, door openings, or fixtures needs 8-10%; and diagonal or pattern layouts need 10-15% or more. Fourth, once you have your total tile count including wastage, convert it into boxes by dividing by the number of tiles per box (which varies by size and brand — always check the specific box you're buying rather than assuming) and rounding up to the next whole box, since partial boxes generally can't be purchased. It's also worth factoring in future repairs: if a tile cracks or gets damaged years after installation, having a few spare tiles from the same production batch means you can replace it with an exact colour and shade match, since tile shades can vary meaningfully between manufacturing batches even for the 'same' product ordered later. Many experienced tilers recommend keeping at least one full extra box aside specifically for this reason, separate from your installation wastage allowance. Finally, if you're tiling multiple rooms or a large area in phases, it's worth ordering all the tile you'll need in one purchase where possible, rather than buying in stages, precisely because of this batch-to-bath colour variation risk — running out mid-project and reordering later carries a real risk that the new batch won't match the tiles already laid, which is a frustrating and sometimes costly problem to discover after the fact.

Wastage percentage is one of the most misunderstood parts of tile planning, and getting it wrong in either direction causes real problems — too little wastage means an urgent, disruptive reorder mid-project with a real risk of batch mismatch, while too much means unnecessary spend on tiles that sit unused in a garage for years. The right percentage depends primarily on two factors: your room's shape and complexity, and the layout pattern you're using. For a simple, mostly rectangular room being tiled in a standard grid pattern (tiles laid in straight rows, aligned with the walls), 5-8% wastage is usually sufficient, since most tiles are used whole and only the edge row needs cutting, typically along one or two sides of the room. For rooms with more complexity — an L-shape, multiple corners, door thresholds, or fixtures like a kitchen island, bathroom vanity, or shower enclosure that the tile has to work around — 8-10% is a safer allowance, since more tiles need partial cuts to fit around these obstacles, and offcuts from one area frequently can't be reused elsewhere due to size or orientation mismatches. Diagonal layouts, where tiles are rotated 45 degrees relative to the walls, typically need 10-15% wastage, because every single edge tile around the entire room perimeter requires an angled cut rather than a straight one, and the geometry of a diagonal cut means more of each edge tile is wasted compared to a straight cut. Complex patterns like herringbone, chevron, or basketweave layouts can push wastage even higher, sometimes to 15-20%, both because of the intricate cutting involved at every boundary and because these patterns are less forgiving of minor tile-to-tile size variation, occasionally requiring an extra tile to be sacrificed to maintain pattern alignment. Tile size itself also plays a role: larger format tiles (800x800mm or bigger) generally have a slightly higher effective wastage rate for a given room, simply because a single miscut or damaged tile represents a larger area loss than it would with a smaller tile, and large tiles are also more prone to handling damage during cutting due to their size and weight. It's worth noting that the installer's skill and the cutting equipment used also affect actual wastage — a wet tile saw with a quality blade, used by an experienced tiler, produces cleaner cuts with less breakage than a manual tile cutter used by someone doing their first tiling job, so if you're doing the work yourself for the first time, it's reasonable to add a percentage point or two above the standard guidance as a buffer for the learning curve. When in doubt, it's generally better to round up to the next full box rather than order the bare minimum calculated quantity, since the cost difference of one extra box is almost always smaller than the cost and disruption of a mid-project reorder, especially if there's any risk the specific tile design is later discontinued or moves to a different production batch.

Yes, tiles per box varies significantly by tile size, and there's no single universal number — it depends on both the tile's physical dimensions and the manufacturer's packaging convention, which is set partly by weight considerations (a box needs to stay within a reasonable weight for handling and transport) and partly by industry convention for that particular size category. As a general pattern, smaller tiles come in boxes with more pieces, since more of them are needed to reach a similar total covered area and a similar box weight. A common 300x300mm tile box often contains somewhere between 12 and 16 tiles, covering roughly 12-17 square feet depending on the exact count. A 600x600mm tile, one of the most popular sizes for Indian homes, is frequently packed 4 tiles to a box, covering approximately 15.5 square feet — though some manufacturers pack these in boxes of 3 or 5 depending on tile thickness and weight. Larger format tiles, such as 800x800mm or bigger, are typically packed 2 or sometimes just 1 tile per box, both because of weight (large tiles are heavy, and a box of several could become difficult and risky to lift) and because large-format tiles are more fragile during transport and benefit from more individual protective packaging. This variation is exactly why relying on a generic 'tiles per box' assumption when planning a purchase is a common source of miscalculation — always check the actual box specification for the specific product and manufacturer you're buying, which is usually printed on the box itself or listed on the retailer's product page, rather than assuming it matches a similar-looking tile from a different brand. It's also worth checking whether the coverage area printed on the box already accounts for typical grout joint width or represents the tile's face area alone, since some manufacturers state box coverage inclusive of a standard joint gap while others state pure tile face area — this distinction becomes more noticeable on larger orders, where even a 2-3% discrepancy between the two conventions can shift your total box count by a meaningful margin. When you're comparing prices between two similar tiles from different brands, it's worth calculating the price per square foot of actual coverage, rather than comparing box price directly, since a lower box price doesn't necessarily mean better value if that box covers noticeably less area than a competing product's box. Finally, if you're ordering for a large project split across multiple purchases or suppliers, confirm the tiles-per-box figure hasn't changed between orders, since manufacturers occasionally adjust packaging conventions between production runs, which can throw off a total box count calculated from an earlier order's packaging.

Grout and adhesive are frequently underestimated in DIY tile planning because the focus naturally goes to the tiles themselves, but running short on either mid-installation is a genuinely disruptive problem — unlike tiles, where a slight shortage just means a delay, running out of adhesive partway through a wall section can mean an uneven pause line that's visible once grouted, and running out of grout can leave a room partially unusable until you can get a matching batch. Grout quantity depends on three main factors: tile size, joint width, and joint depth (which is usually close to the tile's thickness). Smaller tiles need meaningfully more grout per square foot of coverage than larger tiles, simply because there are more linear feet of joint per square foot of floor or wall — a room tiled with 300x300mm tiles has roughly four times as many joint intersections as the same room tiled with 600x600mm tiles, which translates directly into higher grout consumption. Joint width, typically ranging from 2mm for a tight, modern look to 5-6mm or more for a traditional or rustic look, has a near-linear relationship with grout usage — doubling your joint width roughly doubles the volume of grout needed to fill it, so a design choice that seems purely aesthetic can have a real cost and quantity impact worth factoring in before you order. As a rough starting reference, a typical residential installation with standard-size tiles and a 3-4mm joint might use somewhere in the range of half a kilogram to just over a kilogram of grout powder per square metre of tiled area, though this varies enough by specific tile size and joint width that checking the manufacturer's coverage chart for your specific grout product is more reliable than any single rule-of-thumb figure. Tile adhesive quantity is typically estimated based on the notch size of the trowel used to spread it, since a larger notch leaves more adhesive ridges on the substrate before the tile is pressed down, and this is chosen based on tile size (larger tiles generally need a bigger notch and more adhesive per square foot to ensure full, even contact and to accommodate any minor substrate unevenness). A standard estimate for medium-format tiles on a reasonably flat substrate might be in the range of 3-5 kg of adhesive per square metre, but this figure rises meaningfully — sometimes by 50% or more — if the substrate is uneven and requires a thicker adhesive bed to compensate, which is common in older buildings or when tiling directly over an existing uneven floor rather than a freshly screeded surface. Because both grout and adhesive are sold in fixed-size bags, it's sensible to calculate your estimated requirement, add a modest 10% buffer for spillage and mixing waste (some adhesive and grout is inevitably lost during mixing and application, and partially used bags can dry out and become unusable if left for later), and round up to the next full bag, following the same logic as rounding tiles up to full boxes.

It doesn't matter which unit you choose as long as you're consistent throughout the entire calculation, but inconsistency between units is a surprisingly common source of significant miscalculation, and it's worth understanding exactly where the risk lies. The core formula — room area divided by tile area — works correctly in any unit system, provided both the room measurement and the tile measurement are expressed in the same unit before you divide them. Problems arise when a room is measured in feet (a common practice in India for room dimensions) but the tile size is specified in millimetres (the standard way tile sizes are marketed, such as '600x600mm'), and someone divides one by the other without converting them to a common unit first — this produces a meaningless number rather than a genuinely wrong-but-plausible one, since the units don't cancel out correctly, but the resulting error isn't always obvious at a glance, which is exactly why it causes real purchasing mistakes. The safest practice is to pick one unit system for the entire calculation and convert everything into it before doing any division: if you're working in square feet, convert your tile's millimetre dimensions into feet first (divide each dimension in mm by 304.8 to get feet, since there are 304.8mm in a foot), then multiply the two converted dimensions together to get the tile's area in square feet. If you're working in square metres, convert millimetre dimensions to metres instead (divide by 1000) before multiplying. A related and equally common point of confusion is the difference between a tile's nominal size and its actual size — a tile marketed as '600x600mm' is sometimes very slightly smaller than that exact dimension once manufactured, to accommodate a consistent grout joint width across a full installation, and while this difference is usually small enough not to meaningfully affect a quantity calculation, it explains why two tiles both labelled '600x600mm' from different manufacturers might not be perfectly interchangeable in a mixed installation. It's also worth double-checking whether a retailer's stated 'coverage per box' figure is calculated in square feet or square metres, particularly if you're comparing tiles from an international brand that may default to metric figures against a domestic brand using imperial ones, since directly comparing a 'per box' price between the two without confirming the coverage unit can lead to a misleading value comparison. As a general practical habit, it's worth writing down every measurement with its unit clearly labelled as you take it — room length in feet, tile size in millimetres, and so on — rather than trusting yourself to remember which unit each number represents once you're partway through a calculation with several figures in front of you, since this small habit prevents the majority of unit-mismatch errors before they happen.

The underlying area-based calculation — total surface area divided by tile area, plus a wastage allowance — is fundamentally the same for both floors and walls, but several practical factors differ enough between the two applications that treating them identically can lead to under-ordering or an unsuitable tile choice. For floors, the area to be tiled is simply the room's footprint, easily measured as length times width (or the sum of multiple rectangular sections for an irregular room), with deductions for any large fixed features that won't be tiled over, such as a built-in cabinet base, though most homeowners choose to tile straight through under moveable fixtures for future flexibility. For walls, calculating the area requires accounting for height as well, and critically, subtracting the area of any openings that won't be tiled — doors, windows, and in bathrooms, any recessed niches or built-in shelving — since failing to subtract these can lead to a noticeably inflated tile estimate, especially in smaller rooms like bathrooms where door and window openings represent a proportionally larger share of total wall area than they would in a larger room. A typical approach is to calculate the full wall area as if it were solid, then subtract the area of each opening individually, using each opening's actual height and width. Beyond the area calculation itself, floor tiles and wall tiles are frequently different products, not just the same tile applied in two orientations — floor tiles generally need higher slip resistance and greater impact and abrasion durability, since floors bear foot traffic, dropped objects, and furniture movement, while wall tiles can prioritize lighter weight (easier and safer to install vertically) and don't need the same slip-resistance rating, since they're not walked on. Using a wall-rated tile on a floor can create a safety hazard due to inadequate slip resistance, particularly in wet areas like bathrooms, while using a heavier floor-rated tile on a wall is usually structurally fine but may be needlessly expensive and harder to install vertically. Wastage percentages also tend to differ slightly between the two applications: wall tiling around fixtures, corners, and openings (especially in a small bathroom with a shower, basin, and toilet all competing for wall space) often needs a wastage allowance at the higher end of the typical range, sometimes 10% or more, even for a straightforward grid layout, simply because there are more edges and obstacles per square foot of wall area than there typically are per square foot of floor area in the same room. Finally, if you're tiling both the floor and walls of the same room — a bathroom is the most common example — it's worth calculating each surface separately with its own appropriate wastage percentage rather than combining them into one blended estimate, both because the tiles themselves may be different products with different box coverage, and because combining the calculations makes it harder to spot a measurement or unit error in either one before you place your order.