Backsplash Calculator
Kitchen backsplash tile estimate: subway tiles or mosaic sheets for the counter run and the taller section behind the range, plus grout, adhesive and trim.
Your estimate
175 tiles
Tiles needed (incl. 10% waste)
- Backsplash area
- 20.5 sq ft
- Tile to buy
- 22.6 sq ft
- Grout
- 2.1 lb
- Adhesive
- 0.51 gal → 1 × 1 gal pail
- Box extenders
- 3
Show the math
- Main section = (12 ft − range 30 in) × 18 in
- + range section × 30 in − windows = 20.5 sq ft
- Tiles = area ÷ ((tile L + joint) × (tile W + joint)) × (1 + 10%) → 175
- Grout uses the joint-volume formula with 15% extra for small tiles
Shopping list & cost
| Item | Spec | Qty | Cost |
|---|---|---|---|
| Backsplash tile | 3 × 6 in subway | 175 tiles (22.6 sq ft) | — |
| Unsanded grout | 1/16 in joints | 2.1 lb → 1 × 10 lb | — |
| Premixed tile adhesive | 3/16 in V-notch trowel | 0.51 gal → 1 × 1 gal pail | — |
| Outlet box extenders | one per device | 3 | — |
| Edge trim (metal or bullnose) | 2 exposed ends × height | 3 ft (1 piece) | — |
| Silicone caulk | joint at the countertop and inside corners | 1 tube | — |
Prices are what you enter under Advanced options. Estimates only — check stock and pricing with your supplier.
Quick answer A 12 ft kitchen backsplash 18 in high, with a 30 in range section tiled 30 in high, is 20.5 sq ft — 175 tiles of 3 × 6 in subway tile with 1/16 in joints and 10% waste, plus about 2.1 lb of unsanded grout and 3 outlet box extenders. A 3.6 m run of 75 × 150 mm metro tile, 45 cm high, needs 170 tiles.
Method & assumptions
Area = (Run − Range width) × Height + Range width × Range height − Windows Tiles = Area ÷ ((Tile L + joint) × (Tile W + joint)) × (1 + waste %) Sheets = Area × (1 + waste %) ÷ Sheet area Edge trim = Exposed ends × Height
- Run
- total backsplash length along the counter
- Height
- counter to upper cabinets
- Range section
- the taller area behind the cooktop, often to the hood
Assumptions & limits
- Subway and rectangular tile counts include one grout joint per tile; mosaics are sold on ~1 sq ft (300 × 300 mm) sheets.
- Grout uses the same joint-volume formula as the grout calculator, with 15% extra because small-tile jobs waste more.
- Premixed adhesive (mastic) covers about 40 sq ft per gallon on wall tile; use thinset for glass, stone or large tile.
- Waste 10% for straight-set subway; raise it to 15% for herringbone, vertical stack around many outlets, or window returns.
Rounding: purchase quantities are always rounded up to whole units as sold. See our methodology.
Diagram
How to use this calculator
- Measure the full length of the backsplash along the countertop, including the section behind the range.
- Measure the height from the counter to the underside of the upper cabinets (usually 18 in / 45 cm).
- Enter the range width and how high you will tile behind it — often up to the hood or to the ceiling.
- Pick your tile; mosaics are counted in sheets, subway and rectangular tiles individually.
- Count the outlets and switches in the backsplash and the exposed tile ends that need edge trim.
Worked examples
Imperial: 16 ft L-shaped run, 18 in high, no range section, 3 × 6 in subway
- Area = 16 × 1.5 = 24 sq ft
- Tile footprint = 3.0625 × 6.0625 in = 0.129 sq ft → 186 tiles
- +10% = 205 tiles; ≈ 2.4 lb unsanded grout
Metric: 2.4 m run, 50 cm high, 60 cm hob section tiled 70 cm high, 50 mm mosaic
- Area = 1.8 × 0.5 + 0.6 × 0.7 = 1.32 m²
- × 1.10 ÷ 0.09 m² per sheet = 16.1 → 17 sheets
In depth: backsplash planning notes
Measuring a kitchen backsplash
Most backsplashes are a long, shallow strip: the counter run times the 18 in (45 cm) between the countertop and the upper cabinets. The exception is the section behind the range or cooktop, which usually goes higher — up to the hood, often about 30 in, or all the way to the ceiling as a feature. The calculator treats that section separately so you don't under-buy, and lets you subtract a window. Measure every wall segment that gets tile, including short returns at the end of a run and the side of a tall pantry, and add them together for the length.
Small tiles have more cuts relative to their area, especially around outlets, window returns and the ends of the run, so 10% waste is the minimum for subway tile and 15% is safer for herringbone or busy layouts. Mosaic tiles are mounted on mesh sheets about 12 × 12 in (300 × 300 mm), and you buy them by the sheet; subway and rectangular tiles are counted individually, including the grout joint in each tile's footprint. Keep a few spare tiles — matching a backsplash tile after a repair is rarely possible.
Grout, adhesive, outlets and trim
Backsplash joints are usually 1/16–⅛ in, which calls for unsanded grout; a typical backsplash needs only a couple of pounds, so a small bag or premixed tub is enough. Ceramic tile on a dry backsplash is commonly set with premixed mastic, which grabs quickly on vertical surfaces; use thinset for glass, natural stone, large tile and anything behind a sink that will get wet regularly. The joint where the tile meets the countertop and inside corners should be caulked with silicone rather than grouted, because those joints move.
Two details are easy to forget. Outlets and switches in the backsplash need box extenders so the device sits flush with the finished tile surface; turn the power off before removing cover plates. And any tile edge that is exposed — at the end of a run that stops short of a wall, or along the top if there are no upper cabinets — needs a finished edge: a metal or PVC trim profile, bullnose tile or a pencil liner. Count those ends and the calculator adds the trim length.
Reference table
| Tile | Per sq ft · per 20 sq ft backsplash (+10%) |
|---|---|
| 3 × 6 in subway | 7.8 · 171 |
| 2 × 8 in | 8.7 · 191 |
| 4 × 12 in | 2.9 · 65 |
| 2 × 2 in mosaic, 12 × 12 in sheets | 1 sheet · 22 sheets |
| 4¼ × 4¼ in | 7.7 · 171 |
Key facts
- Standard backsplash height
- 18 in (45 cm) to the upper cabinets
- Subway joints
- 1/16–⅛ in, unsanded grout
- Outlets
- box extenders bring devices flush with the tile
- Countertop joint
- caulk, not grout
Tips & common mistakes
- Start the layout from the center of the range or sink so cuts are equal at each end.
- Tile a level line, not the countertop — counters are rarely perfectly level; fill the bottom joint with caulk.
- Turn off power and remove cover plates before tiling; add box extenders so receptacles sit flush and meet code.
- Seal natural stone and unglazed tile before grouting so the grout haze does not stain.
Frequently asked questions
How many subway tiles do I need for a backsplash?
About 7.8 tiles per square foot for 3 × 6 in tile with 1/16 in joints. A typical 20–30 sq ft kitchen backsplash needs 170–260 tiles with 10% waste.
How many square feet is a typical kitchen backsplash?
Commonly 20–35 sq ft: a 12–20 ft counter run at 18 in high, plus a taller section behind the range.
How much extra backsplash tile should I buy?
10% for straight-set subway or squares, 15% for herringbone, diagonal or many outlet and window cuts. Keep a few spares for repairs.
Do I tile behind the stove?
Usually yes, often higher — to the hood or the ceiling — because it is the area that gets the most splatter. Enter it as the range section.
Can I use mastic for a kitchen backsplash?
For ceramic tile on a dry backsplash, premixed mastic is common and easy. Use thinset for glass tile, natural stone, large tile and anything that will get wet regularly.
Sources
- TEC – Skill Set Type 1 Mastic product data sheet (PDF) — accessed : “Approximate coverage: tile up to 6" x 6", 3/16" x 5/32" V-notch trowel – 1 gallon (3.78 L): 41-48 ft²”
- CUSTOM Building Products – VersaBond Professional Tile Mortar (coverage chart) — accessed : “1/4" x 1/4" x 1/4" square-notch: 90 sq. ft. (min) – 100 sq. ft. (max) per 50 lb bag”
- Tile Council of North America – TCNA Handbook (wall installations) — general reference — not cited for a specific figure
- Daltile – backsplash installation resources — general reference — not cited for a specific figure
- NFPA 70 (NEC) – boxes flush with combustible and noncombustible surfaces — general reference — not cited for a specific figure
Default values (yields, coverage rates and densities) are typical figures from manufacturer literature. Always check the label on the product you buy.
Related calculators
- Tile CalculatorCount floor or wall tiles and boxes, including a 100 sq ft bathroom, with joints and overage for straight, offset, diagonal or herringbone.
- Grout CalculatorPounds or kilograms and bags of grout from tile size, thickness and joint width, including 12×24 tile over 100 sq ft.
- Thinset CalculatorBags of thinset by trowel notch, bag weight and back-buttering, including 12×24 tile over 100 sq ft.
Learn more in our guides
Method, waste and worked examples: Tile quantities: layout waste, grout and thinset.
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DIYCalcLab. “Backsplash Calculator.” Oct 19, 2026. https://diycalclab.com/tile/backsplash-calculator/
Estimates only. Verify quantities with your supplier and local building codes. For structural, electrical or safety-critical work, consult a licensed professional. Full disclaimer.