Measure Your Backsplash Area
Measure the length and tiled height of each wall section. Multiply length by height in feet to get square feet, or divide square inches by 144. For L-shaped and U-shaped counters, measure each run separately and add the areas. Give a taller section behind the range its own entry.
Subtract the width × height of windows and other areas you will leave untiled. Do not subtract outlets or switches: their area is small, and cuts around electrical boxes can consume more tile than the opening saves. Measure only the wall you intend to tile. For a floor or another rectangular surface, use the tile calculator.
Standard Backsplash Height and Coverage
The band is usually 18 in — the gap left between a 36 in countertop and upper cabinets hung at 54 in from the floor. Residential code sets no dimension here, so treat 18 in as the norm rather than a rule: 15 to 22 in all show up in real kitchens. If your countertop has a 4 in splash already attached and you're tiling above it, your tile band is 14 in, not 18.
A short backsplash may rise just 4 inches above the counter. Behind a range, tile often extends to the bottom of the hood or up to the ceiling. Enter that taller area as a separate section without counting it twice in the adjoining runs. On a wall with no upper cabinets, the stopping point is a design choice. Under a window, measure from the counter to the sill.
Backsplash Tile Layout and Cuts
A small backsplash can have a high proportion of cuts. Outlets, window corners and the ends of a counter all interrupt rows. Check the starting point with a dry layout so you can see narrow pieces before setting tile.
For large tile with any side longer than 15 inches, most manufacturers recommend an offset of about 33% or less. Follow your tile’s installation instructions; this is manufacturer guidance, not an ANSI requirement. At the countertop-to-wall joint and inside corners, leave movement joints filled with caulk rather than grout.
Do not deduct outlets or switches. Offcuts around them usually cannot be reused. For a small area with many outlets, increase the allowance and keep an extra box from the same batch. The percentage remains your choice.
Straight lay starts at 10% extra tile. Half and third offset start at 12%; diagonal and herringbone start at 15%. Change the allowance for your cuts and spare pieces. This tool shows wall elevations and openings, rather than placing individual tiles.
Exposed edges may need bullnose tile or metal trim. Measure those edge lengths and buy trim separately; this calculator does not estimate it. Use the grout calculator for joints and the thinset calculator for mortar beneath the tile.
How Many Tiles to Buy for a Backsplash
Multiply net area by (1 + extra allowance), divide by one tile’s face area, and round up to a whole tile. Then divide by tiles per box and round up to whole boxes. If the carton lists square feet instead, divide the area including allowance by the box coverage. For mosaics, use the coverage per sheet printed on the package.
For a 10 ft counter with an 18 in backsplash and 3 × 6 in subway tile, straight lay gives:
- Net area: 10 × (18 ÷ 12) = 15 sq ft.
- With the default 10% extra: 15 × 1.10 = 16.5 sq ft.
- Each tile covers (3 × 6) ÷ 144 = 0.125 sq ft; 16.5 ÷ 0.125 = 132 tiles.
- At 40 tiles per box, 132 ÷ 40 = 3.3, rounded up to 4 boxes containing 160 tiles.
Buy all the tile from the same batch. Consider keeping one additional unopened box from that batch for future repairs; add it to the calculated order yourself.