Tile Calculator
Find the number of floor or wall tiles and boxes you need for any room, including a waste allowance for cuts.
Tile Calculator — input your values
What does this construction calculator do?
The tile calculator works out how many floor or wall tiles you need to cover a rectangular room, converting your chosen tile size into square feet and dividing it into the room area.
It adds a waste allowance for cuts, breakage and pattern fitting, then tells you how many boxes to buy based on a typical 10 sq ft per box — always round up when ordering.
Formula and variables
Tiles are sold in mixed boxes — count total square footage, not exact tile counts per box.
| Symbol | Meaning |
|---|---|
| 12 × 12 in tile | 1 sq ft each |
| 12 × 24 in tile | 2 sq ft each |
| 18 × 18 in tile | 2.25 sq ft each |
| Box | ≈ 10 sq ft of coverage |
Worked example
A 12 ft × 12 ft room tiled with 12 × 12 in tiles, ordering with 10% waste.
- Area = 12 × 12 = 144 sq ft.
- Each 12 × 12 tile = 144 sq in ÷ 144 = 1 sq ft.
- Tiles without waste = 144 ÷ 1 = 144 tiles.
- With 10% waste: 144 × 1.1 = 158.4 sq ft → 159 tiles.
- Boxes = 158.4 ÷ 10 = 15.84 → 16 boxes.
Answer: Order ≈ 159 tiles (16 boxes).
Tips and common mistakes
Tips
- Order all your tiles at once — dye lots differ between batches, and a second order may not match.
- For large-format tiles over 18 inches, add an extra 5% for breakage during handling.
- Plan the layout so cut tiles land in the least visible corners, like along baseboards.
- Store spare tiles flat and dry so they match if you ever need to replace one.
Common mistakes to avoid
- Forgetting that offcuts at walls and doorways can eat 10% of the material even in a simple grid layout.
- Using the tile's nominal size (12 in) when it measures slightly less, which undercounts the square footage.
- Ordering exact quantities without spares — matching a discontinued tile later is nearly impossible.
Tile Calculator — frequently asked questions
How many 12×12 tiles do I need for a 12×12 room?
Exactly 144 tiles cover the 144 sq ft room with no waste. With the usual 10% allowance, order about 159 tiles.
How much tile waste should I plan for?
Plan 10% for a standard grid layout and 15% for diagonal, herringbone or brick patterns. Large tiles and rooms with many corners also increase waste.
How many square feet are in a box of tile?
Most boxes cover about 10 sq ft, though larger tiles may come at 8–12 sq ft per box. Check the label — this calculator assumes 10 sq ft.
Do bigger tiles mean more waste?
Yes — the fewer tiles you use, the more each cut-off represents. A 24 × 24 in tile cut once can waste several square feet.
Should I order extra tiles for future repairs?
Yes — keep at least 5% of your order in storage. Tile gets discontinued frequently, and matching later is rarely possible.
Does grout width change the tile count?
Only slightly — grout lines are small fractions of an inch. The 10% waste allowance comfortably covers any grout-width effect.