Tile Waste Calculator
Tiles to order = exact tile count + waste for the layout + spares for repairs. Waste is about 10% for a straight grid, 15% diagonal, 20% herringbone and 25% for large-format tile or a cut-up room. 120 tiles laid diagonally plus 5 spares means ordering 143. Get the exact count from the Tile Calculator.
How it's calculated: Total to order = exact tiles × (1 + layout waste %) + spare tiles for future repairs.
Result appears here
Fill in the fields and press Calculate.
Formula, calculation, assumptions and sources
Waste tiles = exact tiles × layout %
Total to order = exact + waste + attic stock
Run the calculation to see each step with your own numbers.
120 tiles exact, diagonal layout (15%), 5 for attic stock.
Waste = 120 × 15% = 18
Order = 120 + 18 + 5 = 143 tiles
- Layout percentages follow TCNA / trade practice; a room with many small cuts, niches or a busy pattern needs the higher end.
- Attic stock is spare tile from the SAME production lot kept for a future repair — dye lots don't match later.
- Order is in whole tiles; you'll still round up to whole boxes at purchase.
- Isn't 10% a lot of waste?
- It's a minimum for a plain grid. Every perimeter tile is a cut, some crack on the wet saw, and you want spares from the lot. Complex layouts and large tiles waste more, not less.
- What is attic stock?
- A few spare tiles kept from the same production lot for a future repair. Dye lots shift, so a tile bought later to replace a cracked one rarely matches — keep at least a handful, more on a large floor.
- Do I still round up to full boxes?
- Yes. This gives a tile count; at the store you buy whole boxes, so the real order is usually a little above even this figure.
- How much extra tile should I buy?
- At least 10% for a straight grid, 15% for diagonal, 20% for herringbone and up to 25% for large-format tile or a cut-up room, plus a few spares from the same lot. 120 tiles laid diagonally with 5 spares is 143.
Waste allowances
≈ 10% waste for a straight/grid tile or plank layout (cuts + breakage + attic stock). Tile Council of North America (TCNA) Handbook / NWFA guidance. Diagonal or pattern layouts 15%+. Editable.
About the Tile Waste Calculator
The Tile Waste Calculator takes an exact tile count — the number with no allowance, from the Tile Calculator — and works out how many to actually order once cuts, breakage and attic stock are added. The overage is driven by the layout: a plain grid needs about 10%, a diagonal or herringbone pattern 15–20%, and large-format tile or a cut-up room up to 25%.
What you enter
- Exact tiles needed — The count with no waste — from the Tile Calculator.
- Layout
- Extra tiles for future repairs — Keep a few spare from the same lot. 1–2% of the job, minimum a handful.
What you get back
- Waste tiles — the exact result of the calculation.
- Total to order — the exact result of the calculation.
The formula, a worked example, the assumptions behind it and the sources are shown in full below the calculator.
Related calculators
- Tile Calculator — Tiles and boxes needed for a floor or wall, including an allowance for cuts.
- Grout Calculator — Grout quantity for a tiled area from tile size and joint width.
- Flooring Calculator — Flooring material (planks or boxes) for a room, including waste.
Related articles
- Exact Quantity vs Recommended Order Quantity — Every BuildNumerics calculator shows two figures on purpose — the exact geometric answer, and a separate, waste-adjusted number you can actually order.
- Tile, Grout and Thinset: What Does Each Material Do? — Tile is the finished surface, thinset bonds it to the substrate, and grout fills the joints between tiles — each calculated a different way.
Part of the Tile & Flooring calculators.