Floor Tile Calculator
Turn a room's square footage into boxes of floor tile, with the waste allowance that cut tiles and breakage demand.
Calculator
Free, runs entirely in your browser, and your numbers never leave your device. Results are estimates for planning only.
What this calculator does
Tile breaks, gets cut at the edges, and needs spares for future repairs, so a waste allowance is essential. This tool applies a layout-appropriate waste percentage to your floor area and converts it into boxes of tile to buy.
How to use it
- Enter the room length and width.
- Pick the layout — diagonal and patterned tile waste more at the cuts.
- Enter the coverage per box from the tile carton.
- Leave waste blank for the layout default, then read the boxes.
The formula
Area = length × width. Order area = area × (1 + waste%). Boxes = ⌈order area ÷ pack coverage⌉.
Example calculation
A 10 ft × 12 ft floor, straight layout, boxes covering 15 sq ft, default 10% waste:
- Floor area: 10 × 12 = 120 sq ft
- With 10% waste: 120 × 1.10 = 132 sq ft
- Boxes: ⌈132 ÷ 15⌉ = 9 boxes
Result: 9 boxes — set aside a few spare tiles from the same lot for repairs.
Buying and planning tips
- Go to 15% waste for diagonal tile and more for intricate patterns or many small cuts.
- Keep at least a few spare tiles; a cracked tile is much easier to replace from the same lot.
- Dry-lay a row first to plan cuts and avoid thin slivers at the walls.
Common mistakes to avoid
- Ordering only the exact area with no allowance for cuts and breakage.
- Using a straight-lay allowance for a diagonal or herringbone tile pattern.
- Not buying spares, then finding the tile discontinued when one cracks.
Assumptions and limits
- Default waste: straight 10%, diagonal 15%, herringbone 18%.
- Heavily patterned floors and rooms with many cuts may need a higher allowance.
- Coverage per box is taken from your input; confirm it on the carton.
Frequently asked questions
How do I calculate square footage for tile?
Multiply the room's length by its width to get the floor area in square feet, then add a waste allowance for cuts and breakage. This calculator does both and converts the result into boxes of tile to buy.
How much waste should I add for floor tile?
Plan for about 10% on a straight layout, 15% for diagonal, and 18% for herringbone. Add more for small rooms with lots of edge cuts.
Why does tile need a waste allowance at all?
Edge tiles get cut, some tiles break during cutting or handling, and you want spares for future repairs — the allowance covers all three.
How many spare tiles should I keep?
Keep at least a square yard's worth, or a few tiles per lot. Matching a discontinued tile later is often impossible.
Does a bigger tile change the waste?
Large-format tiles can waste more at cuts because each offcut is bigger, so lean toward the higher end of the allowance.
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