Backsplash Tile Calculator
Work out tile and box quantities for a kitchen or bathroom backsplash, which needs a different waste allowance than a floor.
How this calculator works
The calculator first finds your room area (Length × Width, in square feet), then finds the area of a single tile by converting its length and width from inches to square feet: (tile length in × tile width in) ÷ 144 (144 square inches in a square foot).
A waste allowance is added to the room area to cover cuts, breakage, and pattern layout (diagonal or offset patterns need more). The number of tiles is the waste-adjusted area divided by the area of one tile, rounded up. Boxes needed is that same area divided by how many square feet one box covers, rounded up to a full box.
For rectangular formats such as 12×24 tiles: a 12×24-inch tile covers 2 ft², so 100 ft² of floor area requires 50 tiles before adding waste. Always add your waste allowance (typically 10–15%) to the project area before determining the final quantity to purchase.
Example calculation
Project: a 10 ft counter run at 18 in tall (1.5 ft), plus 3 ft² of exposed wall beside the range, using mosaic sheet tile that covers 1 ft² per sheet, with 15% waste.
- Counter wall = 10 × 1.5 = 15 ft²
- Plus exposed wall = 15 + 3 = 18 ft²
- With 15% waste = 18 × 1.15 = 20.7 ft²
- Sheets needed = 20.7 ÷ 1 ≈ 21 sheets
At roughly $10–$18 per sheet, that’s about $210–$380 in tile — backsplashes are usually bought by coverage area rather than individual piece count since mosaic sheets are the standard format.
Buying & material guidance
Straight-lay patterns typically need only 7–10% waste; diagonal layouts, herringbone, or rooms with lots of corners and cutouts (like bathrooms with fixtures) should use 15% or more. Large-format tiles (anything over 15″) also tend to need more waste allowance since offcuts are harder to reuse.
Always buy tile from the same dye lot when possible — color can shift slightly between production runs. It’s also worth keeping a full spare box after the job for future repairs, since matching tile years later is often impossible.
This tool uses the same calculation engine as our full Tile Calculator, with guidance tailored to this project type.
Frequently asked questions
How much tile do I need for a kitchen backsplash?+
Measure your counter-to-cabinet wall length times height (commonly 18 inches) for the base area, add any exposed wall beside the range or window, then apply a 15% waste allowance for a standard layout — higher for mosaic or herringbone patterns with more cuts.
How many tiles do I need for a 12x12 room?+
For a 12 ft × 12 ft room (144 ft²) using standard 12×12-inch tiles (1 ft² each) with a 10% waste allowance (158.4 ft²), you need 159 tiles (158.4 rounded up) — or 11 boxes if each box covers 15 square feet (10.56 rounded up). This is an illustrative example; use the calculator above with your exact room dimensions and box coverage for precise project estimates.
How much extra tile should I buy for waste?+
A 10% waste allowance covers most straight-lay installations. Increase this to 15% or more for diagonal patterns, herringbone layouts, or rooms with many cuts around fixtures and corners.
Should I buy tile by the box or by the piece?+
Tile is almost always sold by the box, and most retailers require full-box purchases. This calculator rounds up to the nearest full box so you know exactly how many to order.
How much does tile installation cost per square foot?+
Professional tile installation typically runs $5–$14 per square foot including labor and materials, depending on tile type (ceramic is cheapest, natural stone and large-format porcelain cost more) and pattern complexity. Tile material alone usually ranges from $1–$8 per square foot before installation.
How many tiles do I need for a bathroom floor?+
A typical small bathroom (5 ft × 8 ft, 40 ft²) with 12×12-inch tiles and a 15% waste allowance (bathrooms have more cuts around fixtures) needs about 46 tiles, or roughly 3–4 boxes at 15 ft² per box. Enter your exact room dimensions above for a precise count.
What size tile is best for a small bathroom?+
12×12-inch or smaller tiles are common for small bathroom floors since they're easier to cut around fixtures and generate less waste. Larger-format tiles (18×18-inch and up) can make a small room look bigger but usually mean more cutting and a higher waste allowance.
How much tile do I need for a shower wall?+
Shower tile needs depend on wall height (typically 7–8 ft for a full surround) and should use a higher waste allowance — 15–20% — to account for corners, niches, and plumbing cutouts. Measure each wall separately, sum the square footage, then apply the waste allowance before dividing by tile size.
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