CalculateY
Quick Answer
A 10 x 12 foot area (120 sq ft) with 12 x 12 inch tiles and 1/8-inch grout joints requires approximately 131 tiles (with 10% waste), or 14 boxes at 10 tiles per box.
Area Dimensions
Tile Size
Common Examples
| Input | Result |
|---|---|
| 10 x 12 ft, 12x12 in tiles, 1/8 in grout, 10% waste | 120 sq ft, 119 tiles, 131 with waste, 14 boxes |
| 8 x 10 ft, 6x6 in tiles, 1/8 in grout, 10% waste | 80 sq ft, 304 tiles, 335 with waste, 34 boxes |
| 15 x 15 ft, 18x18 in tiles, 3/16 in grout, 10% waste | 225 sq ft, 98 tiles, 108 with waste, 11 boxes |
| 5 x 8 ft, 4x4 in tiles, 1/8 in grout, 10% waste | 40 sq ft, 357 tiles, 393 with waste, 40 boxes |
How It Works
The Formula
Effective Tile Area = (Tile Length + Grout Width) x (Tile Width + Grout Width) / 144
Tiles Needed = ceil(Floor Area / Effective Tile Area)
Tiles with Waste = ceil(Tiles Needed x (1 + Waste% / 100))
Boxes = ceil(Tiles with Waste / Tiles per Box)
Where:
- Tile Length and Tile Width are in inches
- Grout Width is the gap between tiles in inches (commonly 1/16 to 3/16 inch)
- 144 converts square inches to square feet
- Waste% accounts for cuts at edges, broken tiles, and fitting
Grout Width Impact
The grout joint adds a small amount to each tile’s effective coverage. For large tiles (12x12 or 18x18), the grout impact is minimal. For small tiles (2x2 mosaic or 4x4), the grout width has a proportionally larger effect and reduces the number of tiles needed per square foot.
Standard Tile Sizes
Common floor tile sizes include 6x6, 12x12, 12x24, 18x18, and 24x24 inches. Wall tiles are often 3x6, 4x4, 4x12, or 6x8 inches. Mosaic tiles come in sheets, typically 12x12 inches per sheet. When using mosaic sheets, enter the sheet dimensions as the tile size.
Waste Percentages
- 10% for straightforward rectangular areas with minimal cuts
- 15% for rooms with alcoves, angles, or obstacles requiring more cuts
- 20% for diagonal layouts or complex patterns
- 5% for large areas with very few cuts
Worked Example
For a 10 x 12 foot floor with 12x12 inch tiles and 1/8-inch (0.125 in) grout: Effective tile area = (12 + 0.125) x (12 + 0.125) / 144 = 12.125 x 12.125 / 144 = 147.02 / 144 = 1.0210 sq ft per tile. Tiles needed = ceil(120 / 1.0210) = ceil(117.53) = 118 tiles. With 10% waste: ceil(118 x 1.10) = ceil(129.8) = 130 tiles. At 10 tiles per box: ceil(130 / 10) = 13 boxes. Total tile coverage in 13 boxes = 130 tiles, covering 132.73 sq ft of effective area.