📐 Area to Tile
🔲 Tile Specifications
Tiles to Buy
—tiles
Net Area
—
sq ft
Order Area (w/ waste)
—
sq ft
Grout Bags (25 lb)
—
Thinset Bags (50 lb)
—
⚠️ Buy extra and keep spares — Tile lots change. If you need to replace one cracked tile in 3 years and the lot is discontinued, matching is nearly impossible. Store a box of spares flat in a cool, dry location.
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How to Calculate Tile Quantities
// Net area
Area = Length × Width
// Order area including waste
Order area = Area × (1 + waste %)
Tiles = CEIL(Order area ÷ sq ft per tile)
Area = Length × Width
// Order area including waste
Order area = Area × (1 + waste %)
Tiles = CEIL(Order area ÷ sq ft per tile)
Waste Factor by Layout
| Layout | Waste | Reason |
|---|---|---|
| Straight grid, simple room | 10% | Clean cuts; offcuts reusable |
| Straight grid, complex room | 15% | Multiple cuts for outlets, pipes, L-shapes |
| Diagonal (45°) | 20% | Every wall requires a diagonal cut — large waste triangles |
| Herringbone | 20–25% | Direction changes + pattern matching waste |
| Subway tile, straight | 10–15% | Small tiles = more cuts at perimeter |
Thinset and Grout Coverage Reference
| Product | Coverage | Notes |
|---|---|---|
| Thinset mortar (50 lb bag) | 40–50 sq ft | With 3/16" V-notch trowel for most floor tile |
| Thinset (50 lb), large tile | 30–40 sq ft | 12"+ tile needs larger notch trowel, more mortar |
| Sanded grout (25 lb bag) | 70–150 sq ft | For joints 1/8" and wider |
| Unsanded grout (10 lb bag) | 50–100 sq ft | For joints narrower than 1/8" |
Frequently Asked Questions
How many 12x12 tiles do I need for a 10x10 room?
A 10×10 room is 100 sq ft. A 12×12 tile is 1 sq ft. With 15% waste, you need 115 tiles. This calculator does that automatically — just enter the room dimensions and select 12"×12" from the tile size dropdown.
Should I use sanded or unsanded grout?
Use sanded grout for joints 1/8 inch and wider — it's stronger and resists shrinkage. Use unsanded grout for joints narrower than 1/8 inch, and for polished stone tiles where sand could scratch the surface. Most standard floor tile uses sanded grout.
Do I need cement board under floor tile?
For floors, yes — cement board (like Durock or HardieBacker) provides a stable, moisture-resistant substrate that won't flex under foot traffic. Tile set over flexible subfloor (plywood alone) will eventually crack at the grout joints. Most installers use 1/2" cement board screwed to plywood, then tiled over it.