Calculate exactly how many tiles and boxes you need. Handles waste allowance for any pattern.
Ordering the wrong number of tiles is one of the most expensive mistakes in home renovation. Order too few and you face a project halt mid-installation while you try to find matching product — and if the manufacturer's dye lot has changed, the tiles from a second batch will look subtly different than the first. Order too many and you waste hundreds of dollars on unused tile. This calculator handles the geometry precisely and applies proper waste allowance so you order exactly the right amount for your specific tile size, room dimensions, and installation pattern.
The fundamental calculation is straightforward: divide the total area you need to cover by the area of one tile, then add waste. The complexity comes from unit conversion (rooms measured in feet, tiles measured in inches), waste percentage varying by installation pattern, and box quantities that determine your actual purchase amount. Standard method: measure room length x width in feet to get square feet. Convert to square inches by multiplying by 144 (since 1 sq ft = 144 sq inches). Divide by one tile's area (tile length x tile width in inches). Multiply by (1 + waste percentage). Round up to the nearest full box based on tiles-per-box. For a 12 ft x 10 ft floor using 12x12 inch tiles: 120 sq ft = 17,280 sq inches. Divided by 144 sq inches per tile = 120 tiles. Add 10 percent waste = 132 tiles. If boxes contain 12 tiles = 11 boxes. Our area calculator handles more complex room shapes with alcoves or bump-outs, and our concrete calculator uses similar principles for subfloor preparation.
| Tile Size (inches) | Area per Tile (sq in) | Tiles per 100 sq ft | Best For |
|---|---|---|---|
| 2 x 2 (mosaic) | 4 | 3,600 | Accent walls, shower niches |
| 4 x 4 | 16 | 900 | Small bathroom floors, backsplash |
| 6 x 6 | 36 | 400 | Kitchen backsplash, small floors |
| 4 x 12 (subway) | 48 | 300 | Backsplash, shower walls |
| 6 x 24 (plank) | 144 | 100 | Wood-look floors |
| 12 x 12 | 144 | 100 | Most floor applications |
| 12 x 24 | 288 | 50 | Large format floors and walls |
| 24 x 24 | 576 | 25 | Modern large-format floors |
| 24 x 48 | 1,152 | 13 | Contemporary showrooms, feature walls |
Waste is not optional — it accounts for the tiles that get cut, broken, or wasted during installation. The right waste percentage depends on your installation pattern and tile size. Straight-lay patterns (grid alignment with grout lines matching in both directions) waste 10 percent because most cuts happen only at room edges. Diagonal patterns rotate tiles 45 degrees to run diagonally across a room — this doubles the number of cut tiles because every edge involves a diagonal cut, so budget 15 percent waste. Herringbone patterns (interlocking L-shapes made from rectangular tiles) waste 15 to 20 percent because every tile is cut at the row starts and ends. Chevron patterns (V-shapes made from parallelogram-cut tiles) waste 15 to 20 percent for similar reasons. Large format tiles (24 inch and larger) waste more because when you cut them, you get fewer usable pieces per cut than smaller tiles, and broken large tiles can't be salvaged for small edge pieces. Small mosaic tiles waste less because the individual tiles are already small and cuts produce useful edge pieces. Rooms with lots of corners, columns, alcoves, or angles need an extra 5 percent baseline waste beyond pattern-based allowance. Our tile calculator lets you select the appropriate waste percentage for your specific project rather than applying a one-size-fits-all default.
| Installation Pattern | Waste Allowance | Notes |
|---|---|---|
| Straight-lay (grid) | 10% | Standard grid alignment, minimum waste |
| Brick / Offset | 10-12% | Rows shifted 50% or 33% |
| Diagonal | 15% | 45-degree rotation adds cut edges |
| Herringbone | 15-20% | Every tile cut at row edges |
| Chevron | 15-20% | Parallelogram cuts increase waste |
| Large format (24"+) | 15% minimum | Bigger tiles yield fewer usable cuts |
| Complex room shapes | +5% extra | Add on top of pattern allowance |
Ceramic tile is the most common and affordable option, ranging from 1 to 8 dollars per square foot. It's made from clay fired at moderate temperatures and typically comes in glazed varieties suitable for walls and light-use floors. Porcelain tile is denser and harder than ceramic (fired at higher temperatures), ranging from 3 to 15 dollars per square foot. Porcelain is water-resistant enough for outdoor use, more durable for high-traffic floors, and available in realistic wood-look and stone-look varieties that have transformed modern flooring. Natural stone (marble, travertine, slate, granite) ranges from 7 to 30 dollars per square foot and requires sealing and specific care but provides genuinely unique material variation that manufactured tile can't match. Glass tile for backsplashes runs 8 to 30 dollars per square foot. Beyond the tile itself, budget for: thinset mortar at 0.30 to 0.50 dollars per sqft, grout at 0.20 to 0.40 dollars per sqft, backer board if needed for floors at 1 dollar per sqft, spacers and edge trim at 20 to 50 dollars per project, and tools (tile cutter or wet saw) at 100 to 400 dollars if buying rather than renting.
A typical residential bathroom is 5 ft x 8 ft = 40 sq ft. Different tile choices produce very different quantities. Using 12x12 inch tiles: 40 sq ft x 144 sq in/sq ft = 5,760 sq inches, divided by 144 sq inches per tile = 40 tiles. Add 10 percent straight-lay waste = 44 tiles. At 12 tiles per box = 4 boxes. Using 6x6 tiles: 40 sq ft = 5,760 sq inches divided by 36 sq inches per tile = 160 tiles + 10 percent = 176 tiles. At 20 tiles per box = 9 boxes. Using 12x24 large format tiles: 40 sq ft = 5,760 sq inches divided by 288 sq inches per tile = 20 tiles + 15 percent waste (for large format) = 23 tiles. At 6 tiles per box = 4 boxes. Notice that box count is similar across tile sizes because manufacturers scale box quantity to weight and volume — small tiles pack more per box, large tiles fewer. Your total cost depends much more on price per tile than on tile size for typical residential quantities. Our area calculator helps calculate square footage for L-shaped or irregular bathrooms, and our unit converter handles feet-to-inches conversions if you prefer metric measurements.
Grout width (the gap between tiles) technically affects tile count, though the effect is minor for typical installations. Standard grout widths are 1/16 inch for rectified porcelain, 1/8 inch for standard glazed tiles, 3/16 inch for tiles with slight size variation, and 1/4 inch for large-format or handmade tiles. Wider grout lines mean fewer tiles technically fit in the same area, but the difference is usually less than 2 percent — well within your waste allowance. Grout choice affects appearance dramatically: 1/16 inch produces a nearly seamless look ideal for modern designs, 1/8 to 1/4 inch is standard for most residential installations, and wider grout lines emphasize the grid pattern for a more traditional look. Grout color matters as much as width: matching grout to tile blends into a single visual field, contrasting grout (dark grout with light tile, or white grout with dark tile) emphasizes the grid pattern. Epoxy grout costs more but resists staining and doesn't need sealing — worth the extra cost for kitchen floors, showers, and high-use bathrooms. Standard cement-based grout is fine for most residential wall applications.
Beyond installation waste, buy an extra 1 to 2 boxes for future repair inventory. Tiles crack from dropped heavy objects, moved furniture, or foundation settling. Being able to swap a broken tile 5 years later with a perfect match requires having tiles from your original dye lot — manufacturers change dye lots between production runs, and even the same product SKU from a store today will look subtly different than the same SKU 6 months ago. Store extra tiles wrapped in original packaging in a climate-controlled area (not a hot attic or damp basement). Track the manufacturer, SKU, and dye lot number (usually printed on the box) for future reference. For discontinued products, having backup stock is even more critical since you may not be able to buy any matching tile in the future at any price. Some homeowners photograph the box label and store it with their home records. The extra cost of buying 2 more boxes upfront (60 to 150 dollars for a typical residential product) is minor insurance against a full-floor replacement if you can't source a match for a single broken tile later.