Tile Calculator
It converts a floor or wall area into a tile count and a box count, including a waste allowance for cuts and breakages.
Tiles to order
132
Tile coverage
1.000 ft²
Tiles (exact)
120.0
Tiles with waste
132
Boxes to buy
14
Tiles in those boxes
140
Spare tiles
8
Diagonal and herringbone layouts need 15–20% waste rather than 10%. Check every box carries the same dye lot number before you start.
What it calculates
It converts a floor or wall area into a tile count and a box count, including a waste allowance for cuts and breakages.
Why it matters
Tile is sold by the box and dye lots vary between batches, so a second trip may not match. Ordering right the first time matters.
Who it's for
Anyone tiling a bathroom, kitchen or floor, and tradespeople quoting materials.
Formula
- A
- Area to be tiled, in square feet
- a
- Area of one tile
- w
- Waste allowance for cuts and breakage
Worked example
120 sq ft with 12×12 inch tiles, 10% waste, 10 per box
- 1One 12-inch tile = 1 sq ft
- 2120 ÷ 1 = 120 tiles
- 3×1.10 waste = 132 tiles
- 4132 ÷ 10 per box
132 tiles, which is 14 boxes
How the tile calculator works
Tile area in square feet is width times height in inches divided by 144. Dividing the room area by the tile area gives the exact count, which is then increased by the waste allowance and rounded up — you cannot buy part of a tile, or part of a box. Grout lines are ignored because they are far smaller than the waste allowance that covers them.
Tile area in square feet is width times height in inches divided by 144, so a 12-inch tile covers exactly one square foot. Dividing the room area by the tile area gives the exact count, which is then raised by the waste allowance and rounded up.
Grout lines are ignored deliberately: they slightly reduce the tiles needed, and the effect is far smaller than the waste allowance that covers it.
Common mistakes
- Ordering no waste allowance; 10% is the minimum for a straight layout.
- Forgetting that diagonal and herringbone layouts need 15–20% because of the extra cuts.
- Buying boxes from different dye lots, which can show as a visible color shift.
Tips and best practice
- Order a full spare box and keep it — matching a discontinued tile years later is close to impossible.
- Check the dye lot number is identical across every box before you start.
Frequently asked questions
How many tiles do I need?
Divide the area to be tiled by the area of one tile, then add 10% for cuts and breakage. A 12-inch tile covers exactly one square foot.
How much waste should I allow for tile?
10% for a straight grid layout, 15–20% for diagonal or herringbone patterns, which generate far more cuts.
Do I need to account for grout lines?
Not in practice. Grout lines slightly reduce the number of tiles needed, and the effect is much smaller than the waste allowance.
Should I buy a spare box?
Yes. Tile lines are discontinued and dye lots vary, so a spare box is the only reliable way to repair damage later.
Related calculators
Methodology & trust
- Formula source
- Standard tile estimation with trade waste allowances.
- Last updated
- 2026-07-28
- Privacy
- Every calculation runs in your browser. No inputs are sent to a server or stored.
- Accessibility
- Keyboard navigable, labeled inputs and WCAG AA color contrast.