Tile Calculator — tiles, boxes & cost for floors and walls

This tile calculator converts your room's area and your chosen tile size into the exact number of tiles, boxes, and total cost you need for the job, with a waste allowance built in for cuts and breakage. It works for both floor tile and wall tile projects, and you can enter your area directly or let the tool calculate it from length and width.

Buying the wrong quantity of tile is one of the most common — and most expensive — mistakes in a home renovation: too little means a delayed project and a possible dye-lot mismatch on a reorder, while too much wastes money on materials you can't return. Arb Digital built this tile calculator, part of a full library of free everyday tools, to help homeowners and contractors get the number right the first time.

What This Tile Calculator Does

The calculator takes your total area (either entered directly or computed from room length times width), divides it by the coverage of a single tile based on its length and width, and applies your waste percentage to account for cuts, breakage, and future repairs. It then rounds up to a whole number of tiles, works out how many full boxes that requires based on tiles per box, and multiplies by your cost per box for a total materials budget. The tool supports both US units (feet and inches) and metric units (meters and centimeters), and works equally well for floor tile or wall tile projects.

How to Use the Tile Calculator

1. Choose your unit system — US feet/inches or metric meters/centimeters — and whether you're tiling a floor or a wall.
2. Enter your area. Either type the total square footage (or square meters) directly, or switch to "Enter length & width" and let the tool multiply them for you.
3. Enter your tile size. Check the tile box or spec sheet for the exact length and width — common sizes include 12"×12", 18"×18", and 24"×24" for floors, and smaller sizes like 4"×4" or 3"×6" subway tile for walls.
4. Set your grout gap and waste percentage. The default waste of 10% covers straight cuts in a simple rectangular room; increase it for diagonal layouts, complex room shapes, or a first-time DIY job.
5. Enter tiles per box and cost per box from your supplier's packaging, and the calculator shows the boxes needed and total cost.

The Formula Behind the Tile Calculator

The core calculation is: Tiles Needed = ⌈(Area ÷ Tile Coverage Area) × (1 + Waste% ÷ 100)⌉, where the tile coverage area is the tile's length times its width, and the result is always rounded up to a whole tile. For example, a 100 sq ft room tiled with 12"×12" (1 sq ft) tiles needs 100 ÷ 1 = 100 tiles before waste; adding 10% waste gives 100 × 1.10 = 110 tiles. Boxes needed is simply ⌈Tiles Needed ÷ Tiles per Box⌉, and total cost is Boxes Needed × Cost per Box. This rounding-up approach at every stage is standard industry practice, since a partial tile or partial box can't actually be purchased — most professional installers and suppliers, as referenced by general guidance from the Tile Council of North America, recommend ordering a full waste allowance up front rather than trying to source an exact matching batch later.

Choosing the Right Waste Percentage

The waste percentage you choose should reflect both your room's layout and your tile pattern. A simple rectangular room with a straight grid layout typically needs only 8–10% extra for basic cuts along the edges. A room with jogs, alcoves, or an L-shape needs closer to 12–15%, since more cuts are required and more offcuts are unusable. A diagonal (45-degree) layout or a herringbone pattern can push waste to 15–20%, because diagonal cuts generate more waste per tile and pattern-matching limits how offcuts can be reused. First-time DIY installers should also lean toward the higher end of these ranges, since breakage and cutting mistakes are more common without experience — buying slightly more tile up front is far cheaper than a mid-project scramble to match a discontinued dye lot.

It's also worth buying a small number of extra tiles beyond your calculated total — often called "attic stock" — to keep on hand for future repairs. Tile manufacturers frequently discontinue or change dye lots over time, so a cracked tile years down the road may be impossible to match exactly without spare tiles saved from the original job.

Floor Tile vs. Wall Tile — What's Different

Floor tile and wall tile projects use the same core math, but a few practical differences matter. Floor tile is typically larger (12"×12" up to 24"×24" or bigger for modern large-format tile) and needs to account for room shape, doorways, and any fixtures like a floor drain or hearth. Wall tile is often smaller — think 3"×6" subway tile or small mosaic sheets — and needs extra waste allowance for cuts around outlets, switches, windows, and corners, since walls tend to have more obstructions per square foot than open floor space. When tiling a shower or backsplash wall, many installers budget 15% waste or more purely because of the number of small cuts required around fixtures and edges. Selecting the correct surface in this calculator is mainly a reminder to adjust your waste percentage accordingly — the underlying tile-count math is identical for both surfaces.

Grout Gap and Layout Considerations

The grout gap you plan to use affects the finished look and the amount of grout you'll need, though it has only a small effect on the raw tile count for most standard gap widths (typically 1/16" to 1/4" for most residential tile). Larger-format tile usually looks best with a narrower grout line, while smaller tile like mosaics or subway tile often uses a slightly wider joint for a more traditional appearance. Whatever gap you choose, keep it consistent across the whole job — uneven grout lines are one of the most visible signs of an amateur installation, and professional installers use tile spacers to keep every joint uniform.

Comparing Tile Sizes and Layout Patterns

Larger-format tiles generally mean fewer tiles for the same area, but not necessarily a lower cost, since bigger tiles usually cost more per unit and per box. Running this tile calculator with two or three candidate sizes — say 12"×12", 18"×18", and 24"×24" for the same 100 sq ft room — lets you compare total tile count, total boxes, and total cost side by side before committing to a size. Larger tiles also tend to look better with fewer visible grout lines in an open room, but they can be harder to install on uneven subfloors and are heavier and more prone to cracking if not laid on a perfectly flat surface. Smaller tiles are more forgiving during installation and offer more design flexibility for patterns, but require more grout lines and generally more labor time per square foot.

Layout pattern also changes practical waste beyond the basic percentage. A straight grid pattern (tiles aligned in even rows and columns) is the most material-efficient layout and generates the least waste. A brick or running-bond pattern (each row offset by half a tile) is nearly as efficient but produces slightly more small offcuts along the edges. Diagonal layouts, herringbone, and other decorative patterns look distinctive but consume noticeably more material because triangular and angled offcuts are harder to reuse elsewhere in the room — this is the main reason those layouts call for a higher waste percentage in the calculator above.

Budgeting for the Full Tiling Project

Tile itself is usually only part of the total project cost. A complete budget also typically includes thinset mortar or adhesive, grout, tile spacers, a trowel and mixing tools if you're not renting them, edge trim or transition strips, and sealer for natural stone tile. Professional installation labor, if you're hiring it out, is frequently priced per square foot and can add a substantial amount on top of materials — get a few quotes locally rather than assuming a flat national rate, since labor costs vary enormously by region and by the complexity of the layout. Using this calculator to lock down your exact tile quantity first makes it much easier to get an accurate materials quote from a supplier, since most tile retailers price and package by the box rather than by loose individual tiles.

Common Mistakes to Avoid

• Forgetting the waste allowance entirely — ordering the exact calculated tile count with zero buffer almost always leaves you short once cuts and breakage happen.
• Measuring the room incorrectly — always measure the actual tileable area, subtracting large permanent fixtures like a built-in tub or island if they won't be tiled underneath.
• Mixing dye lots — tile color can vary noticeably between production batches, so buy all your tile in one order from the same lot number where possible.
• Ignoring pattern-specific waste — diagonal and herringbone layouts need meaningfully more waste allowance than a simple straight grid.
• Not keeping spare tiles — a small stock of extra tile makes future repairs possible without an exact-match reorder years later.

Related Free Tools From Arb Digital

Pouring a slab, footing, or post before you tile? Check the concrete calculator for material quantities. Planning the rest of the renovation budget? Try the electricity bill calculator or the road trip cost calculator for other project planning. The area converter and length converter are useful for converting room measurements between unit systems. Browse everything at our free online tools hub.

Frequently Asked Questions

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