Tile Calculator
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About the Tile Calculator
Tile is unforgiving to under-order: a matching dye lot may be gone by the time you're three rows short, and a visible color shift across one wall reads as a mistake forever. Over-ordering hurts less but wastes real money on premium tile. The fix is a proper count with an honest waste factor before you buy.
Enter the area's dimensions and your tile's size (any size — the common formats are just presets of the same math), pick straight or diagonal waste, and you get the exact count, the coverage area, and each tile's face area. For multiple rooms or walls, run each and sum — or add the areas first if the tile matches.
Need the area itself first? Measure it with the Square Footage Calculator
The Tile-Count Formula
Everything reduces to face areas in the same unit:
Tiles = (Area in in²) ÷ (tile width × tile length) Order = Tiles × (1 + waste%) → rounded up
Worked example: a 10 × 12 ft floor is 120 sq ft = 17,280 in². With 12″ × 12″ tiles (144 in² each) that's exactly 120 tiles; adding 10% cut waste makes the order 132 tiles. The same floor in 12″ × 24″ tile needs 66.
Tiles per Square Foot by Size
The common formats, with a 100 sq ft example order at 10% waste (all computed by this calculator's formula):
| Tile size | Tiles per sq ft | 100 sq ft + 10% waste |
|---|---|---|
| 3″ × 6″ (subway) | 8.00 | 881 tiles |
| 12″ × 12″ | 1.00 | 111 tiles |
| 6″ × 24″ (plank) | 1.00 | 111 tiles |
| 12″ × 24″ | 0.50 | 56 tiles |
| 18″ × 18″ | 0.44 | 49 tiles |
| 24″ × 24″ | 0.25 | 28 tiles |
Boxes vary by brand — divide your tile count by the tiles-per-box printed on the carton, and round the boxes up too.
Ordering & Layout Tips
The habits that separate clean tile jobs from short orders:
- Buy everything in one order and check dye-lot numbers match across boxes — lots shift color slightly between production runs.
- Use 15% waste for diagonal, herringbone, or any layout with a pattern repeat; every border row gets cut and offcuts often can't be reused.
- Square your layout with the 3-4-5 rule: measure 3 ft along one wall and 4 ft along the other — the diagonal between marks reads exactly 5 ft when the angle is square.
- Dry-lay a row before setting: it exposes awkward slivers at walls, which you fix by shifting the starting line, not by cutting 1-inch strips.
- Keep a few spares after the job — a matching repair tile years later is worth far more than the shelf space.
If your room is far from rectangular, split it into rectangles, run each, and sum the tile counts before applying the box math.
Frequently Asked Questions
How do I calculate how many tiles I need?
Divide the area by one tile's face area, then add 10% for cuts (15% for diagonal layouts) and round up. A 120 sq ft floor in 12×12 tiles: 120 tiles exact, 132 with waste. The calculator handles the unit conversions for any tile size.
How many 12x12 tiles do I need for 120 square feet?
A 12″ × 12″ tile covers exactly 1 sq ft, so 120 tiles cover it exactly — order 132 to include 10% cut waste. For diagonal layouts, order 138 (15%).
What is the 3-4-5 rule for tile?
A layout-squaring check based on the right triangle: mark 3 ft along one reference line and 4 ft along the perpendicular one — the diagonal between the marks measures exactly 5 ft only if the lines are truly square. Multiples (6-8-10) work over longer runs.
Why do I need 10–15% extra tile?
Edge rows get cut and the offcut often can't be used elsewhere; tiles break in handling; and patterns need alignment sacrifices. Straight layouts lose about 10%, diagonal and herringbone more like 15% — plus breakage insurance and future repair spares.
Do grout lines change the tile count?
Slightly, in your favor: grout gaps mean each tile occupies a bit more floor than its face area, so a count that ignores grout runs marginally high. That margin is deliberate — it's the safe direction against dye-lot risk.
How many boxes of tile is that?
Tiles per box varies by brand and size (often 8–12 for 12×12, fewer for large formats). Divide the calculator's tile count by your carton's printed count and round up — and confirm all boxes show the same dye-lot code.
Methodology. This calculator uses standard construction and material-estimation formulas. It is reviewed and maintained by the Vast Calculators editorial team.
Last updated · July 2026
Results are estimates for general use; verify critical figures independently.