Tile Calculator
Tiles needed = area ÷ the area of one tile, plus a cut allowance, then ÷ tiles per box, rounded up. A 10 × 12 ft floor in 12 × 12 in tiles is 120 tiles exact, 132 with 10% for cuts — 14 boxes of 10. For layout-based overage, use the Tile Waste Calculator.
How it's calculated: Tiles = area ÷ (tile length × tile width) × (1 + cut allowance); boxes = tiles ÷ tiles per box, rounded up.
Result appears here
Fill in the fields and press Calculate.
Formula, calculation, assumptions and sources
Coverage area = Length × Width
Tiles = Coverage area ÷ (tile length × tile width)
Boxes = ⌈ Tiles including waste ÷ tiles per box ⌉
Run the calculation to see each step with your own numbers.
A 10 ft × 12 ft floor, 12 in × 12 in tiles, 10 per box, 10% cut allowance.
Area = 120 ft²; one tile = 1 ft²
Tiles = 120 ÷ 1 = 120 exact
With 10%: ⌈132⌉ = 132 tiles → ⌈132 ÷ 10⌉ = 14 boxes
- Rectangular area. For an L-shaped room, split it into rectangles and add the results.
- The area is the net tiled area — deduct large fixed obstructions (a kitchen island footprint, a bath) if they are not tiled.
- Grout-joint width is not deducted — it is small relative to the cut allowance and is normally ignored for ordering.
- The box count rounds up; a partial box is still a full purchase.
- Why buy extra tiles?
- Every edge and around every obstruction needs a cut piece, some tiles break, and dye lots change — keeping a few spare tiles from the same lot saves a mismatched repair later. 10% is a common minimum for a simple layout.
- Does grout width matter?
- Only slightly. A 1/8–3/16 in joint changes the count by 1–3% on a typical tile, which is well inside the cut allowance, so BuildNumerics doesn't deduct it.
- How many 12x12 tiles do I need for a 10x12 room?
- 120 tiles to cover 120 ft² exactly, or 132 with a 10% cut allowance — 14 boxes of 10. One 12 × 12 in tile covers 1 ft², so the count equals the square footage before waste.
- How many boxes of tile do I need?
- Work out the tile count with your cut allowance, divide by the tiles per box printed on the carton, and round up. 132 tiles at 10 per box is 14 boxes — a partial box is still a full purchase.
Area division
Standard geometry. Unit conversions per NIST SP 811.
Cut/waste allowance
≈ 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 Calculator
The Tile Calculator works out how many tiles and how many boxes a floor or wall needs, including an editable allowance for cuts, waste and future repairs. Enter the area to cover and the tile size or the box coverage. Grout and thinset are separate — see the Grout and Thinset calculators.
What you enter
- Area length
- Area width
- Tile length — The long side of one tile.
- Tile width — The short side of one tile.
- Tiles per box — Check the box — it varies by tile.
- Cut allowance — 10% for a straight layout; 15%+ for diagonal or patterned; add more for large-format or a broken-up room.
What you get back
- Coverage area — the exact result of the calculation.
- Tiles needed — shown as the exact figure and, separately, a recommended figure with your waste allowance added.
- Boxes needed — Boxes are already sized for the tile count with the cut allowance included — buy this many.
The formula, a worked example, the assumptions behind it and the sources are shown in full below the calculator.
Related calculators
- Grout Calculator — Grout quantity for a tiled area from tile size and joint width.
- Thinset Calculator — Thinset mortar quantity for a tiled area from tile size and trowel notch.
- Tile Waste Calculator — Extra tiles to buy for cuts, breakage and future repairs.
- Floor Area Calculator — Total floor area of a room or a set of rooms.
- 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.