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Tile Calculator
Enter the area to be tiled and your tile size to get the tile count and the number of boxes to buy. The waste allowance covers cuts at edges, breakage and spares — skipping it is the most common reason tile jobs run one box short.
Results update as you type. Estimates only — confirm final quantities before ordering.
The formula
Tiles = Area ÷ Tile area × (1 + Waste %)
Boxes = Tiles ÷ Tiles per box (rounded up)
The tile count is rounded up to whole tiles and the box count to whole boxes, because neither tiles nor boxes are sold in fractions. Waste is applied before rounding, so the allowance survives in the final count.
Worked example
Example: a 120 ft² bathroom floor with 12 in × 24 in tiles, 10% waste, 5 tiles per box.
- Tile area: (12 × 24) ÷ 144 = 2.00 ft² per tile
- Tiles: 120 ÷ 2 × 1.10 = 66 tiles
- Boxes: 66 ÷ 5 = 13.2 → 14 boxes
Reference chart
| Tile size | Area per tile | Tiles per 100 ft² |
|---|---|---|
| 4 × 4 in | 0.11 ft² | 990 |
| 6 × 6 in | 0.25 ft² | 440 |
| 12 × 12 in | 1.00 ft² | 110 |
| 12 × 24 in | 2.00 ft² | 55 |
| 18 × 18 in | 2.25 ft² | 49 |
| 24 × 24 in | 4.00 ft² | 28 |
Frequently asked questions
How much waste should I add for tile?
Ten percent is the standard allowance for a straight (grid) layout in a rectangular room. Use 15% for diagonal, offset/brick or herringbone patterns, small rooms with many cuts, and large-format tiles, which waste more per cut.
Should I buy extra tile beyond the waste allowance?
Yes — keep at least a few spare tiles from the same production lot for future repairs. Tile colors and calibers vary between dye lots, and a tile bought a year later often will not match.
Does the grout joint change how many tiles I need?
Slightly: grout joints mean each tile covers a touch more than its face area, so a strict face-size calculation overestimates by a small margin. The standard waste allowance more than covers the difference, so the simple method is safe.
How do I measure the area to tile?
Measure length × width for each rectangular section and add them. For floors, most installers tile the full footprint including under appliances; deducting large fixed features like a tub is optional and the waste allowance covers the difference either way.
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- Drywall Calculator — Sheets of 4×8 and 4×12 drywall for your wall and ceiling area.
- Concrete Calculator — Cubic yards and bag counts for slabs, patios and pads.
Sources & method: Tile estimating practice and waste allowances per the TCNA Handbook (Tile Council of North America); cross-checked against Inch Calculator — Tile Calculator.