Tile Calculator
Find out how many tiles you need for a floor or wall: enter the area and your tile size, add a waste allowance for cuts and breakage, and get the exact count plus what to buy.
Result
| Exact tiles (with waste) | |
| Area of one tile |
Units & conversions used
Imperial inputs are square feet for the area and inches for tile dimensions; results are plain tile counts. Metric inputs are converted first: 1 m² = 10.7639 ft², 1 cm = 0.3937 in.
Formula & source
tiles to buy = ⌈ area ÷ tile area × (1 + waste%) ⌉
Source: basic area division — no authority needed. The 10% waste allowance is a common DIY practice to cover cut pieces, chipped tiles and future repairs; it is a rule of thumb, not a standard. Diagonal, herringbone or Versailles patterns generate more offcuts and typically need 15–20%.
Worked example (you can verify by hand)
Input: 100 ft² floor, 12×12 in tiles, 10% waste.
- Tile area: (12 × 12) ÷ 144 = 1 ft²
- Exact tiles: 100 ÷ 1 = 100
- With 10% waste: 100 × 1.10 = 110
Expected output: 110 tiles to buy.
Limitations — what this cannot do
- Counts tiles only. Thinset/mortar, grout, spacers, backer board and tools are not included — estimate those separately.
- Assumes rectangular tiles of uniform size laid in a grid. Narrow grout joints are ignored (they change the count only slightly); very wide joints or irregular stone layouts need a different approach.
- Does not plan the layout: border rows, centered patterns and cuts around fixtures still need a dry-lay on site.
- Tiles are sold by the box — round the result up to full boxes, and keep a few spare tiles for future repairs.
FAQ
How many 12×12 tiles do I need for 100 square feet?
Each 12×12 in tile covers 1 ft², so 100 ft² needs 100 tiles exactly. With a 10% waste allowance for cuts and breakage, buy 110 tiles.
Is 10% extra enough for tile waste?
For a straight grid layout in a simple rectangular room, 10% is the common DIY allowance. For diagonal layouts, herringbone, or rooms with many corners and fixtures, use 15–20% instead.
Do I need to account for grout lines?
This calculator ignores grout joint width, which is fine for standard 1/8–3/16 in joints — the difference is small. Very wide joints slightly reduce the tile count, which only adds to your margin.
What about broken or miscut tiles?
That is exactly what the waste allowance is for. Miscuts around doorways, vents and edges plus the occasional chipped tile are normal, especially for DIY installers.
Should I buy extra boxes beyond the calculated amount?
Round up to full boxes since tiles are sold that way, and keep a few spare tiles from the same dye lot — finding an exact color match years later is difficult.