Tile Calculator: Floor & Wall Tile Count, Box & Grout Estimator
Use this tile calculator to estimate exact ceramic, porcelain, or stone tile pieces and boxes needed for floors, backsplashes, and shower surrounds. Includes grout joint widths, layout waste, and companion mortar estimates.
Purchase 13 boxes (130 tiles) to guarantee dye-lot match. Also pick up 2 bags of thinset mortar and 54 lbs of grout.
| Surface Area to Tile | 120 sq ft |
|---|---|
| Nominal Tile Size | 12 × 12 in |
| Grout Joint Spacing | 0.125" |
| Base Tiles Required (Exact) | 117.5 pieces |
| Total Tiles with 10% Waste | 130 pieces |
| Cartons / Boxes Needed (10 / box) | 13 boxes (130 tiles) |
| Thinset Mortar (50 lb bags) | 2 bags (~65 sq ft/bag) |
| Grout Estimate (Sanded) | 54 lbs (approx. 3 x 25lb bags) |
📐 Show Formula and Default Assumptions
We believe all home improvement estimates should be transparent and verifiable. Below is the exact math running in this browser tool:
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Tile Area with Joint Spacing:
Tile Effective Area = (Tile Width + Joint Width) × (Tile Length + Joint Width)Incorporates grout spacer width into each tile module for accurate piece counts. -
Tile Box Packaging:
Boxes to Buy = ceil( Total Tiles Needed / Tiles Per Box )Calculates whole cartons based on standard manufacturer piece packaging. -
Thinset Mortar Coverage:
50 lb Mortar Bag ≈ 60 to 75 sq ft with a 1/4" × 3/8" notched trowelApproximate guideline for setting medium format floor tiles on cement backer board.
Note: All default assumptions (waste %, coverage rates, container yields) can be adjusted directly in the input fields above to match your project specifications.
How to Measure Walls and Floors for Tiling
- Measure the surface area: For floors, multiply length by width. For shower walls, calculate each wall separately (width × height) and sum them together.
- Deduct non-tiled cutouts: For bathroom walls, subtract bathtub openings or prefabricated shower pans that will not receive tile.
- Account for tile size: Convert tile dimensions to feet or meters. A standard 12" × 24" tile equals exactly 2.0 square feet before grout spacing.
- Select grout joint width: Standard floor tiles use 1/8" (3mm) or 3/16" (5mm) joints. Rectified porcelain can use narrow 1/16" (1.5mm) joints with leveling clips.
- Add cutting scrap: Add 10% for basic grid layouts, 12% to 15% for running bond (brick pattern), and 15% to 20% for herringbone or diamond patterns.
- Verify subfloor deflection: Ceramic and porcelain tile requires a rigid subfloor with an L/360 deflection rating (or L/720 for natural stone). Standard 3/4-inch plywood over 16-inch on-center joists is the minimum framing baseline.
- Back-butter large format tiles: For any tile measuring 12x24 inches or larger, use the flat side of the trowel to spread a thin layer of mortar across the entire back of the tile before pressing into the ridged bed. This guarantees the 95% mortar contact coverage required by TCNA standards in wet areas.
How the Tile Calculation Works (Worked Example)
Consider tiling an 8 ft by 6 ft bathroom floor (48 sq ft) using 12" × 12" porcelain tiles with 1/8" grout lines, packaged 10 tiles per box:
- 1. Net Floor Area: 8 × 6 = 48 sq ft.
- 2. 10% Waste Factor: 48 × 1.10 = 52.8 sq ft.
- 3. Individual Tile Area: 12" × 12" = 1.0 sq ft per tile.
- 4. Exact Tiles Required: 52.8 ÷ 1.0 = 53 tiles.
- 5. Box Count: 53 tiles ÷ 10 tiles/box = 5.3 boxes.
- 6. What to Buy: Round UP to 6 boxes (60 tiles total).
- 7. Setting Materials: 1 bag of 50 lb modified thinset mortar (covers ~65 sq ft) and one 10 lb bag of sanded grout.
Popular Tile Formats, Box Piece Counts & Trowel Sizes
| Tile Nominal Size | Area Per Tile | Typical Box Qty | Recommended Notch Trowel |
|---|---|---|---|
| 3" × 6" Subway Tile | 0.125 sq ft | 80 - 100 tiles (10 - 12.5 sq ft) | 1/4" × 1/4" Square Notch |
| 12" × 12" Ceramic Floor | 1.00 sq ft | 10 - 14 tiles (10 - 14 sq ft) | 1/4" × 3/8" Square Notch |
| 12" × 24" Porcelain Plank | 2.00 sq ft | 6 - 8 tiles (12 - 16 sq ft) | 1/2" × 1/2" Square Notch |
| 6" × 36" Wood-Look Plank | 1.50 sq ft | 8 - 10 tiles (12 - 15 sq ft) | 1/2" × 1/2" Square Notch |
| 24" × 24" Large Format | 4.00 sq ft | 3 - 4 tiles (12 - 16 sq ft) | 1/2" × 1/2" with Back Buttering |
Frequently Asked Questions About Tile Calculator
When should I use sanded vs unsanded grout?
Use sanded grout for all grout joints 1/8" (3mm) wide or wider. The sand aggregate prevents cracking and shrinkage. Use unsanded grout only for joints narrower than 1/8", typically on polished marble or delicate glass tile that sand could scratch.
Why is 10% waste the standard minimum for tile?
Tile cutting produces partial tiles that cannot always be reused, especially around toilet flanges, heating registers, and corner cut-ins. Occasional breakage during cutting is inevitable, making 10% the minimum safe reserve.
How much thinset mortar do I need per square foot?
A standard 50 lb bag of dry thinset mortar covers roughly 60 to 75 square feet when using a 1/4" × 3/8" trowel for 12x12 tiles. For large format tiles (12x24 and larger) using a 1/2" trowel, coverage drops to 40 to 50 square feet per bag.
What does "tile run" or "dye lot" mean?
Tile is manufactured in kiln batches called dye lots and calibers. Tiles from different lots can have slight shade variations or sub-millimeter size differences. Always buy enough tile from the same lot at once.
How do I calculate tiles for a niche or shower curb?
Measure the depth and perimeter of the niche or curb, calculate its surface area, and add it to your wall area. Remember to account for bullnose or aluminum edge trim pieces (like Schluter Jolly) measured in linear feet.
Where should flexible silicone caulk be used instead of hard grout?
Never use rigid grout at changes of plane—such as where the tiled floor meets the tiled wall, where the wall meets a bathtub rim, or in inside shower corners. These joints experience natural building movement and must be sealed with 100% color-matched silicone sealant to prevent cracking and leaks.