Backsplash Calculator
Count the tiles or mosaic sheets a kitchen or bathroom backsplash needs — wall area minus openings, with cutting waste included.
How many tiles does a backsplash need?
A backsplash is a small, very visible patch of wall — usually the 18 inches between countertop and cabinets — so the count is simple area work: measure the wall, take out any real openings, and divide by the tile. The tiles are small, the cuts are many, and a broken tile in a feature pattern is obvious, which is why the waste allowance earns its keep here.
Tiles = (wall area − openings) × (1 + waste) ÷ tile area · Boxes = area with waste ÷ coverage per box
Example: a 10 ft kitchen wall, 18 in high, is 15 sq ft. In 3 × 6 in subway tile (0.125 sq ft each) that is 120 tiles exactly — 132 tiles with the 10% allowance, and 2 boxes at the typical 10 sq ft of coverage per box.
Sheets change the counting, not the area
Mosaics arrive as mesh-backed 12 × 12 in sheets, and the count runs on sheets: one sheet per square foot, whatever the little tiles on it are doing. Outlet and switch cutouts are nibbled out of a sheet with nippers — that loss is exactly what the waste allowance is for, so leave outlets out of the openings field. Windows and doors are the openings worth subtracting, because they are whole tiles, not nibbles.
| Tile | Area each | Pieces per sq ft |
|---|
| 3 × 6 in subway | 0.125 sq ft | 8 |
| 4 × 4 in | 0.111 sq ft | 9 |
| 6 × 6 in | 0.25 sq ft | 4 |
| Mosaic sheet 12 × 12 in | 1 sq ft | 1 sheet |
Setting and finishing materials ride on the same area: run it through the thinset calculator for the bags that set these tiles and the grout calculator for the joints — a backsplash grouts with unsanded grout at tight joints, and one small box usually does a whole kitchen.
Frequently asked questions
How high is a standard kitchen backsplash?
18 inches (about 46 cm) is the standard counter-to-cabinet height. Full-height backsplashes run the tile up to the ceiling or the top of the cabinets in the range area — measure that section as its own rectangle and add the areas together.
Do I subtract electrical outlets?
No. An outlet interrupts part of one or two tiles, and the cut pieces are waste — that is what the allowance is for. Subtract only genuine openings you will not tile: windows, doors, a pass-through.
Should I buy mosaic sheets or loose tile?
Sheets are faster to set and keep tiny tiles aligned, but cost more per square foot and show a sheet outline if the spacing between sheets differs from the spacing within them. Loose subway tile is the budget classic and forgiving to lay in a running bond.
How much extra should I keep after the job?
A few tiles from the same dye lot, stored flat. A cracked tile five years from now can only be matched from the same production run — the spare box in the garage is the cheapest insurance in the kitchen.
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