Free Tile Calculator Online

Tile Calculator: How Many Tiles You Need for a Floor

Buying tile comes down to one question with a deceptively fiddly answer: how many pieces cover this floor without leaving you short at the last row? This calculator divides your floor area by the area of a single tile, adds a cushion for cuts and breakage, and rounds the result up to the nearest whole tile — because no supplier sells three-quarters of a tile. Enter the floor area, the tile's length and width in inches, and a waste percentage, and the tile count updates immediately as client-side math in your browser.

The part people usually get wrong doing this by hand isn't the division — it's forgetting the waste allowance, or forgetting to round up afterward. A floor that needs exactly 118.2 tiles by pure division still needs 119 whole tiles at minimum to actually finish the job, and that's before accounting for the pieces that get cut down to fit an edge, break during handling, or need to be scrapped because a pattern didn't line up. This tool builds both of those steps in so the number you see is the number you can hand to a supplier.

How to Calculate Tile Quantity with This Tool

The interface asks for exactly the measurements a tile order needs:

1. Enter the floor area you're tiling, and pick whether that number is in square feet or square meters.
2. Enter the tile's length and width in inches — tile dimensions are always entered in inches here, since that's how tile is sized and sold at nearly every retailer regardless of what unit the room itself was measured in.
3. Adjust the waste percentage if you want something other than the 10% default — a bump up is worth considering for a diagonal layout or a pattern with a lot of cuts, discussed further below.
4. If you know how many tiles come in a box, enter that number too, and the tool also computes how many full boxes to buy, rounded up the same way as the tile count.
5. Read the result: tiles needed, and boxes needed if you supplied a box size, both shown as whole numbers ready to hand to a supplier or contractor.

Why People Need to Calculate Tile Quantity

A tile count feeds directly into ordering, budgeting, and scheduling for several kinds of projects:

• Ordering tile for a bathroom, kitchen, or entryway floor. Getting the count right the first time avoids a slow, expensive second order — tile is frequently sold in limited production runs or dye lots, so a follow-up box weeks later might not match the original shade exactly.
• Budgeting a renovation before committing to a tile style. Running a few different tile sizes through the calculator quickly shows how a larger-format tile (say 18-inch squares instead of 12-inch) reduces the piece count and, often, the labor time to install it.
• Comparing box-based pricing across suppliers. Once you know the tile count, dividing by tiles-per-box tells you how many full boxes to buy, which is usually how tile is actually priced and sold rather than by the individual piece.
• Planning a DIY install with a realistic cut allowance. First-time tile setters break and miscut more pieces than an experienced installer, so understanding the waste percentage — and being willing to raise it — heads off a mid-project trip back to the store.
• Estimating extra tile to keep on hand for repairs. Many installers deliberately order a little beyond the calculated minimum so a cracked tile years later can be replaced with an exact match instead of a close-but-different substitute.

The Formula and What the Waste Percentage Covers

The core formula is floor area divided by the area of one tile, multiplied by one plus the waste percentage, then rounded up to the next whole tile:

Step	Example: 120 sq ft floor, 12in × 12in tile, 10% waste
Tile area	(12 ÷ 12) × (12 ÷ 12) = 1 sq ft per tile
Raw tile count	120 ÷ 1 = 120 tiles
With 10% waste added	120 × 1.10 = 132 tiles
Rounded up to a whole tile	132 tiles (already whole in this case)

That 10% default waste allowance is this tool's assumption for what a typical straight-lay installation loses to edge cuts, occasional breakage, and a handful of pieces cut wrong along the way — it's a commonly used starting point, not a guarantee that your specific room will land exactly there. A small room with lots of corners, a diagonal or herringbone layout, or a first-time DIY install can easily eat more than 10% in cuts, so bumping the waste percentage up to 15% or 20% for those situations is a reasonable adjustment, and the tool lets you change it freely rather than locking in the default.

A second example at different numbers shows how tile size changes the outcome: a 200 square foot room tiled with 18-inch by 18-inch tile (2.25 square feet each) needs 200 ÷ 2.25 = 88.9 tiles before waste, then × 1.10 for the same 10% allowance comes to about 97.8, which rounds up to 98 tiles. If those tiles come 10 to a box, that's 98 ÷ 10 = 9.8, which rounds up to 10 full boxes — note that the box count gets its own independent round-up rather than simply reusing the tile count's rounding, since a box that's 98% full still has to be bought whole.

Tile size has a bigger effect on the final count than most people expect going in. Doubling the tile's linear dimensions — say moving from a 12-inch tile to a 24-inch tile — quadruples the tile's area, which means the room needs roughly a quarter as many pieces, not half as many. That's worth knowing before comparing two tile options purely on a per-piece price, since a larger, more expensive-per-tile option can still work out cheaper overall once the piece count drops that sharply, and it typically installs faster too since there are fewer individual pieces to set, level, and grout.

Mistakes That Lead to an Order That's Short

Rounding down anywhere in this calculation is the single most common way people end up short at the last row — if a spreadsheet or mental math produces "131.6 tiles," the honest answer is 132 whole tiles, not 131, because a supplier doesn't sell partial pieces and a job stops dead without that last one. Underestimating the waste percentage for a complicated layout is the second-biggest gap: a diagonal pattern, a room with a lot of jogs and closets, or herringbone tile all produce meaningfully more cut waste than a simple square layout in a rectangular room, and 10% is really a baseline for the easy case. It's also worth double-checking that the tile dimensions you entered match the tile's actual face size rather than its nominal size — a tile marketed as "12x12" sometimes measures slightly under that once you account for the manufacturing tolerance, though for most home projects the difference is small enough not to matter. Finally, remember that grout line width isn't part of this calculation; a wider grout joint slightly reduces how much floor a given tile count covers, which is one more reason the waste allowance exists as a cushion rather than treating the raw division as a hard minimum.

Manual Calculation vs. Using This Tool

The math behind a tile order is simple in isolation but has several places to slip up when done by hand:

• Working it out with a calculator app. Dividing area by tile size is one step, but converting tile dimensions from inches to the same unit as the floor area, then applying a waste percentage and rounding correctly, adds several more chances for an error to creep in.
• A big-box retailer's in-store tile calculator. Many flooring retailers offer a similar tool at checkout, though it's tied to whatever tile you're already standing in front of rather than something you can use to compare several options before you shop.
• Asking the installer to order. A contractor will typically calculate and order tile as part of a full quote, which is convenient but means you're trusting their waste assumptions rather than seeing the math yourself.
• Spreadsheet formulas. A simple =CEILING formula handles the rounding correctly once set up, but you still have to build in the unit conversion and waste percentage yourself, and re-verify the formula each time you change tile size.
• This calculator's metered API. For a flooring retailer's quoting page or an app that helps customers estimate multiple rooms at once, the same area/waste/rounding logic is available as a metered API endpoint returning tile and box counts as JSON — see the API documentation for the request format.

Why does the tile count round up even when the exact number is close to a whole tile?

Because you can't purchase a fraction of a tile — even a calculated value of 131.02 tiles means you need 132 whole tiles to physically finish the floor, since that last 0.02 of a tile is still a full tile once you're standing in the store.

Should I increase the waste percentage for a diagonal or patterned layout?

Generally yes. The 10% default is a reasonable baseline for a straightforward grid layout in a simple rectangular room; diagonal layouts, herringbone patterns, and rooms with a lot of jogs, alcoves, or fixtures to cut around typically lose more material to cuts, so many installers plan for 15-20% waste in those cases.

Does the tile area calculation account for grout lines?

No — tile area is computed from the tile's own length and width only. Grout joints take up a small amount of additional floor space between tiles, which is one more reason the waste percentage exists as a buffer rather than treating the raw tile-count division as an exact figure.

What happens if I don't know how many tiles come in a box?

The box count is optional — leave that field blank and the tool still gives you the total tile count you need. You can always divide that number by whatever box size your supplier quotes once you're ready to place the order.

Is 10% waste enough for a first-time DIY tile job?

It's a reasonable starting point, but first-time installers often cut and break more pieces than an experienced tiler, so many people doing their first tile job choose to raise the waste percentage a bit rather than risk running short mid-project.

Does a larger tile size really reduce the total I need to buy?

Yes, and by more than a simple ratio suggests. Because tile area grows with the square of its linear size, a tile twice as long on each side covers four times the floor per piece, so switching from a 12-inch tile to a 24-inch tile roughly quarters the piece count for the same floor area — a useful thing to check before assuming a bigger tile is automatically the pricier option once you account for how few of them the job actually needs.

Related Construction Tools

Tile is just one piece of most flooring projects. Start with the square footage calculator to nail down the exact area of an irregular room before tiling it, or use the concrete calculator if the tile is going over a slab you still need to pour. If part of the space is an outdoor path or bed instead of tiled floor, the mulch and gravel calculator handles that loose-material math, and the paint calculator covers the walls once the floor is finished.