Tile Calculator
Tile Size Changes the Count More Than You'd Expect
Swap a 12 in × 12 in tile for an 24 in × 24 in tile in the same room and the tile count doesn't halve by coincidence — it drops to a quarter, because area scales with the square of the side length. That nonlinear relationship is why guessing a tile count from a room's square footage alone is unreliable without knowing the tile's actual footprint.
The Formula
Tile Area = (Tile Length ÷ 12) × (Tile Width ÷ 12)
Tiles Needed = Room Area ÷ Tile Area
Room dimensions go in feet; tile dimensions go in inches, since that's how tile is labeled at the store, so the calculator converts the tile's inch measurements to square feet before dividing. The raw tile count is then increased by a waste allowance — 10% by default — for cuts along edges and around fixtures, and rounded up to a whole tile.
Where This Calculation Matters
- Bathroom and kitchen floors — small rooms with lots of cuts around toilets, vanities, and cabinetry tend to need waste allowances at the higher end of the typical range.
- Large-format tile — 24 in and larger tiles cut the total tile count sharply but raise the cost of a single breakage, since each piece covers more area and typically costs more.
- Pattern layouts — diagonal, herringbone, or mixed-size layouts increase offcuts beyond a simple grid pattern, which is exactly what the waste percentage input is meant to absorb.
Tile Count by Size for a 120 sq ft Room
| Tile Size | Tile Area | Tiles Needed |
|---|---|---|
| 12 in × 12 in | 1.00 sq ft | 132 |
| 18 in × 18 in | 2.25 sq ft | 59 |
| 24 in × 24 in | 4.00 sq ft | 33 |
| 6 in × 24 in (plank) | 1.00 sq ft | 132 |
Note that a 6 in × 24 in plank tile has the same footprint as a 12 in × 12 in tile, so it needs the same count despite looking like a very different product.
How to Use This Calculator
- Enter the Room Length and Room Width in feet.
- Enter the Tile Length and Tile Width in inches, as printed on the box.
- Optionally adjust the Waste % — it defaults to 10%.
- Select Calculate to get the total tile count, rounded up and including the waste allowance.
Related Calculations
Laying planks instead of tile? The Flooring Calculator handles box-based flooring materials, and the Drywall Calculator covers the walls around the same room.