How Much Tile Do I Need? (Calculate Tiles & Boxes)
Part of Interior & Finishes
Quick answer
Multiply the room length × width for the square footage, divide by one tile's coverage in square feet, then add 10% for waste (15% for diagonal or large-format tile) and round up to whole boxes. For example, a 120 ft² floor in 12-inch tile (1 ft² each) needs about 132 tiles with 10% waste — roughly 14 boxes if each box holds 10.
Tile is ordered by the box, but the math starts with area. Get the square footage, convert your tile size to coverage per tile, add a waste margin for cuts and breakage, then round up to whole boxes. Always buy a little extra — dye lots shift between production runs, so matching tile months later is difficult.
The four steps
- Area: room length × width in feet (add up rooms separately for odd shapes).
- Tile coverage: (tile length in ÷ 12) × (tile width in ÷ 12). A 12×12 tile = 1 ft²; a 12×24 = 2 ft².
- Tiles: area ÷ tile coverage, then × 1.10 (or 1.15 for diagonal/large format), rounded up.
- Boxes: tiles ÷ tiles-per-box, rounded up — that's what you actually buy.
Tiles per square foot by size
| Tile size | Coverage each | Tiles per ft² |
|---|---|---|
| 12" × 12" | 1.00 ft² | 1.0 |
| 12" × 24" | 2.00 ft² | 0.5 |
| 18" × 18" | 2.25 ft² | 0.44 |
| 24" × 24" | 4.00 ft² | 0.25 |
| 6" × 24" plank | 1.00 ft² | 1.0 |
| 4" × 4" | 0.11 ft² | 9.0 |
The tile calculator does all four steps live — enter your room size and tile and it returns the tile count, the boxes to buy, and the thinset and grout to finish the job.
FAQs
How many 12x12 tiles are in a square foot?
Exactly one — a 12-inch by 12-inch tile is 1 square foot. So a 200 ft² floor needs 200 tiles before waste, or about 220 with a 10% allowance.
Should I round tile up by box?
Yes. Tile sells in full boxes, so divide your tile count by the tiles-per-box and round up. Keep the leftover tiles — you'll want exact-match pieces for future chips and repairs.