How to Calculate Tiles Needed for a Job
Tile estimation requires converting your floor or wall area into square inches, dividing by each tile's surface area, and factoring in cutting waste. Because tile installers must cut around corners, toilet collars, shower valves, and drains, calculating sufficient waste is critical.
Tile Area (sq in) = Tile Length (in) × Tile Width (in)
Net Tiles Needed = (Surface Length in × Surface Width in) ÷ Tile Area (sq in)
Order Total = Net Tiles × (1 + Waste Percentage)
Net Tiles Needed = (Surface Length in × Surface Width in) ÷ Tile Area (sq in)
Order Total = Net Tiles × (1 + Waste Percentage)
Standard Tile Sizes and Coverage Area
| Tile Dimension | Square Inches | Square Feet per Tile | Tiles per 100 Sq Ft (Net) |
|---|---|---|---|
| 12" × 12" | 144 sq in | 1.00 sq ft | 100 tiles |
| 12" × 24" | 288 sq in | 2.00 sq ft | 50 tiles |
| 6" × 24" | 144 sq in | 1.00 sq ft | 100 tiles |
| 24" × 24" | 576 sq in | 4.00 sq ft | 25 tiles |
| 4" × 12" | 48 sq in | 0.33 sq ft | 300 tiles |
| 3" × 6" (Subway) | 18 sq in | 0.125 sq ft | 800 tiles |
Thinset Mortar and Grout Estimating Rules
In addition to tiles, remember to calculate installation sundries:
- Thinset Mortar: A standard 50-lb bag of modified thinset covers approximately 40 to 50 square feet when using a 1/2" × 1/2" square-notch trowel (for large format 12×24 tiles) or 60 to 75 square feet with a 1/4" × 3/8" trowel.
- Grout: A 25-lb bag of sanded or unsanded grout typically covers 100 to 150 square feet depending on tile thickness and grout joint width.
Frequently Asked Questions
How much extra tile should I order for a bathroom shower?
For shower surrounds with plumbing cuts, niches, and bench seats, plan on 15% to 20% waste. If using herringbone or chevron layout, budget at least 20% to 25%.
What is rectified tile and how does it affect grout?
Rectified tiles have mechanically precision-cut 90-degree edges, allowing tight 1/16" grout joints. Non-rectified (pressed) ceramic tiles have slightly rounded edges requiring at least 1/8" to 3/16" grout joints to absorb sizing variations.