Tile Area Calculator
Tiling a floor, wall, or backsplash starts with one question: how many tiles do you actually need to buy? This tile area calculator works it out from your room dimensions and tile size, then goes further than most estimators: it accounts for grout width, applies a waste allowance matched to your layout pattern, converts the total into boxes to order, and splits the material cost from the installation cost so your budget is complete.
The count rounds up twice: once for the exact tile count, once after adding waste. Boxes always round up to whole boxes; spare tiles are kept for future repairs.
Quick Answer
A 12 by 10 foot room (120 sq ft) with 12 by 12 inch tiles, 1/4-inch grout joints and 10% waste needs 128 tiles: 13 boxes of 10 with 2 spare tiles. At $3.50 per sq ft the tile material costs $462.00, installation at $2.00 per sq ft adds $240.00, for a $702.00 project. Those exact figures are pre-filled in the calculator above; click Calculate tiles and cost to reproduce them.
Key takeaways
- Grout joints are part of every tile’s footprint: a 12-inch tile with 1/4-inch grout covers 1.0421 sq ft, not 1 sq ft. Ignoring grout overstates the tile count.
- Waste is pattern-dependent: 10% for a straight grid, 12% for running bond, 15% for diagonal, 18% for herringbone. The preset buttons set all four.
- Boxes always round up, and the calculator shows the spare tiles that buys you. Keep them: later dye lots rarely match.
- The calculator splits material from installation so you see the true per-square-foot project cost, which is what quotes are compared on.
- Quick Answer
- How to use the tile area calculator
- The tile area formula
- Worked example: a 12 by 10 foot living room
- Choosing a waste factor
- Tiles per 100 square feet, before waste
- What competing calculators miss
- Measuring tips for real rooms
- Frequently asked questions
- Add This Calculator to Your Website
- References
How to use the tile area calculator
Enter nine figures and read the estimate. The results stay hidden until you calculate.
- Enter the room length and width (12 and 10 are pre-filled), and set feet or meters. For a wall, enter wall width and wall height instead.
- Enter the tile length and width in inches from the box or spec sheet, then the grout width. A quarter inch is the standard floor default.
- Set the waste factor by clicking a pattern preset, Straight 10% through Herringbone 18%, or type your own percentage.
- Enter the tile price and choose per sq ft or per tile, then the installation cost per sq ft and tiles per box from the packaging.
- Click Calculate tiles and cost. The headline shows the tile count with waste; the rows below break out room area, box count, spares, and the material/installation cost split.
Invalid inputs are rejected outright: a zero or missing room side (“Enter a room length greater than zero.”), a zero or missing tile side, and negative grout or waste values all show a plain error and no results. Blank cost fields simply mean $0 for that line; blank waste falls back to 10%.
The tile area formula
The count is room area divided by effective tile area, with the grout joint folded into the tile footprint, waste applied on top, and everything rounded up.
Effective tile area = ((tile length + grout) ÷ 12) × ((tile width + grout) ÷ 12)
Boxes = ceil( tiles ÷ tiles per box )
Material cost = room area × price × (1 + waste ÷ 100) (per-sq-ft pricing)
Material cost = tiles × price per tile (per-tile pricing)
Two honest details. First, the waste is applied to the already-rounded-up count, then rounded up again, so a 120 sq ft room never leaves you a fraction of a tile short. Second, with per-square-foot pricing the material cost is charged on the room area plus the waste allowance, which matches how suppliers quote; with per-tile pricing you pay for every tile in the box count, including waste. Installation is always computed on the room area, because that is how installers quote labor. For the labor side in more depth, the tile labor cost calculator breaks out pattern complexity, transition pieces and old-tile removal.
Worked example: a 12 by 10 foot living room
A 12 by 10 foot living room is 120 sq ft. The tile is 12 by 12 inches, the grout joint is 1/4 inch, the pattern is a straight grid at 10% waste, the tile costs $3.50 per sq ft, installation costs $2.00 per sq ft, and the box holds 10 tiles. These are the pre-filled values in the calculator.
Costs follow: material is 120 sq ft × $3.50 × 1.10 = $462.00; installation is 120 sq ft × $2.00 = $240.00; the project totals $702.00. Run these exact numbers through the calculator above and you will get the same figures, which is the point: the tool shows every intermediate line so you can check the arithmetic against your own quote.
Choosing a waste factor
Waste is not a guess; it tracks the layout. Angled cuts at the room edges turn whole tiles into off-cuts, so diagonal and herringbone patterns consume measurably more tile than a straight grid. The table below gives the trade-standard starting points, and the calculator’s preset buttons set them in one click.
| Layout pattern | Waste allowance | Why it wastes this much |
|---|---|---|
| Straight grid | 10% | Simple cuts along two edges only |
| Running bond (brick) | 12% | Offset cuts are predictable but constant |
| Diagonal (45°) | 15% | Triangular cuts at all four walls |
| Herringbone | 18% | Angled cuts at every row end, plus higher breakage |
Add a few percent on top of the pattern allowance when the room has many corners, niches, columns or door thresholds, since each short wall wastes part of a tile. And most installers recommend one extra full box of attic stock beyond the calculation: if a tile cracks years later, a matching spare from the original dye lot is the only reliable fix, because production batches vary in shade and size.
Tiles per 100 square feet, before waste
For quick planning, this table gives the tile count per 100 sq ft for common sizes with a 1/4-inch grout joint, before any waste allowance. Every figure follows the tool’s own formula, so add your pattern’s waste and round up to boxes the same way the calculator does.
| Tile size | Tiles per 100 sq ft (no waste) | Typical use |
|---|---|---|
| 4 × 4 in | 798 | Walls, accents |
| 6 × 6 in | 369 | Walls, small floors |
| 12 × 12 in | 96 | Standard floors |
| 12 × 24 in | 49 | Plank-style floors |
| 18 × 18 in | 44 | Large rooms |
| 24 × 24 in | 25 | Large-format floors |
What competing calculators miss
Tile calculators fall into a few camps, and each leaves something on the table:
- Grout-blind estimators: several count tools divide room area by raw tile area (length × width ÷ 144) and never ask for a grout width. On a 120 sq ft floor of 12-inch tile that overstates the count by about 4 tiles, and the error grows as tiles get smaller and joints get wider.
- Waste as an afterthought: some tools compute an exact count and then suggest buying 5–10% more on top, which double-counts waste if you already applied a factor. This calculator applies the waste factor inside the math, once, with a pattern-matched preset.
- Count-only tools: the basic calculators stop at the tile count. No boxes, no spares, no cost. You are left to convert tiles to boxes at the store counter, where the dye-lot warning matters most.
- Cost guides without tools: the 2026 national cost guides publish the ranges, tile installation labor near $3–$15 per sq ft or $60–$120 per hour, and old-tile removal near $2–$7 per sq ft, but make you do the arithmetic yourself. The installation line in this tool does that arithmetic on your room area.
- The gap this page fills: grout-adjusted counting, one-click pattern waste presets, whole-box rounding with spare tiles, and the material/installation cost split, all on one page, with every line reproducible in the worked example above.
Measuring tips for real rooms
The calculator trusts your measurements, so make them count. Measure each wall at its longest point and round lengths up to the nearest inch; tiny under-measurements compound across a room. For L-shaped rooms, split the floor into two rectangles, run the calculator once per rectangle, and add the box counts. Subtract permanent fixtures, cabinets and closets you will not tile, but include under door thresholds, since every doorway needs tile. Compare the plan against a carpet area calculator if you are weighing tile against carpet for the same room, and price the full project against the floor replacement cost calculator before committing to one material.
Frequently asked questions
153 tiles, with 1/4-inch grout joints and a 10% waste allowance. A 12 by 12 foot room is 144 sq ft; each 12-inch tile covers 1.0421 sq ft including the grout joint; 144 ÷ 1.0421 = 138.2, rounded up to 139 tiles before waste; 139 × 1.10 = 152.9, rounded up to 153 tiles with waste. Change the grout width, tile size or waste and the answer moves with them.
Enter the joint your installer plans, usually 1/4 inch for floors, which is the default here. The Ceramic Tile Foundation notes that ANSI A108.02 sets an absolute minimum grout joint of 1/16 inch, with TCNA guidance calling for at least 1/8 inch on rectified tile and 3/16 inch on calibrated tile. Zero is not a real option: tiles vary slightly in size, and the joint absorbs that variation.
Use the preset buttons: 10% for a straight grid, 12% for running bond, 15% for a diagonal layout, and 18% for herringbone. Rooms with many corners, niches or thresholds deserve the higher end of the range. Most installers also add one full box of attic stock beyond the calculation for future repairs.
Yes. Tile is sold in full boxes, so the calculator rounds the tile count up to the nearest whole box and shows the spare tiles that leaves you. Keep those spares: dye lots vary between production runs, and a box bought months later may not match.
Because the grout joint is part of every tile’s footprint. A 12-inch tile with a 1/4-inch joint occupies 12.25 inches of floor in each direction and covers 1.0421 sq ft instead of 1 sq ft. Over a 120 sq ft room that difference removes about 4 tiles from the count. Calculators that ignore grout width overstate how many tiles you need.
Measure the net tiling area yourself and enter it as a single rectangle. Subtract closets, cabinets and other permanent obstructions, and add small irregular bump-outs into the dimensions. One run covers one rectangular area at a time, so split an L-shaped room into two runs and add the box counts together.
Use whichever your supplier quotes; the calculator handles both. With per-square-foot pricing the material cost covers the room area plus the waste allowance; with per-tile pricing you pay for every tile bought, including waste. Installation is always computed on the room area, since installers quote labor per square foot of floor, not per tile.
It does not price grout or thinset quantities, trim and edging pieces, or subfloor preparation. Joint volume is a separate calculation, covered by the grout volume calculator. Labor uses the simple per-square-foot model; for pattern complexity, transition pieces and old-tile removal, use the tile labor cost calculator.
Yes. This tool is free, runs fully in your browser, and asks for no account, so your room measurements never leave your device. “Copy my results” grabs the tile count, waste allowance and box estimate in one go; “Share results” sends the same summary to a supplier or contractor.
Add This Calculator to Your Website
This calculator is free to embed: take the code below, pick a size to preview it, and paste it on any website.
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References
- Ceramic Tile Foundation. ANSI Standards: A Tile Installer’s Best Friend (ANSI A108.02 Section 4.3.8: grout joint never below 1/16 inch; minimum 1/8 inch for rectified tile and 3/16 inch for calibrated tile in running-bond patterns over 15 inches). Accessed October 24, 2026.
- Architessa. Expert Guide on Grout (ANSI A108.02 Section 4.3.8 text: actual joint at least three times the facial-dimension variation; nominal centerline straight, with allowances for handmade or rustic tile). Accessed October 24, 2026.
- The Tilers Hub. How to Calculate Tile Quantities Accurately (10% waste for standard layouts, 15% for intricate patterns; grout lines reduce the tile count; order from one batch for consistent dye lot). Accessed October 24, 2026.
- Cardinal Decor. Tile Installation Prices: Compare Labor and Material Costs (2026 national planning ranges: tile installation labor near $3–$15 per sq ft or $60–$120 per hour; old-tile removal about $2–$7 per sq ft; cost data checked September 2, 2026). Accessed October 24, 2026.
- ServiceAgent. Price Per Square Foot Calculator (typical tile installation labor $4–$32 per sq ft; old floor removal $1–$6 per sq ft; effective per-square-foot rate as the quote-comparison figure). Accessed October 24, 2026.