How to use this calculator
Measure each continuous run of counter separately, in feet, along the wall. A normal L-shaped kitchen has two runs; a galley has two facing runs; a U has three. Enter them as run 1, 2 and 3, and leave any you do not have at zero.
Then set the height. Counter to the underside of the upper cabinets is commonly 18 inches, and that is the calculator’s default. Measure it anyway — 15 and 20 both exist, and on a 16 foot run the difference between 18 and 20 inches is nearly 3 square feet of tile.
Measuring a real kitchen
Counter to cabinet height
Measure from the counter surface, not from the floor, and measure at both ends of the run. Counters are level; cabinets are hung by people. A quarter inch of difference across a run means the top row gets scribed, which means an extra cut on every tile in that row.
Behind the range
If there is no upper cabinet over the range, the tile usually runs to the hood or to the ceiling. That panel is typically 30 or 36 inches wide and 30 to 42 inches tall — call it 9 square feet, which on a small backsplash can be a third of the whole job. Add it as an extra run at the taller height, or run the calculator twice and add the two results.
Outlets and windows
An outlet takes a fraction of a square foot. Subtracting it saves nothing and costs you accuracy, because tiling around an outlet means two cut tiles and often four. Leave the outlets in the area and add the cut count.
A window over the sink is different. If it is 3 feet by 2 feet inside the tiled zone, that is 6 square feet you genuinely do not tile — subtract it, but expect four cut edges around the opening and a jamb return if the window is recessed.
Substrate and thickness
A backsplash goes straight onto painted drywall in a dry kitchen, which surprises people who have read about shower waterproofing. Scuff the paint with 80 grit, wipe the dust off and set the tile with a white polymer-modified thinset. The one exception is behind a sink where water regularly runs down the wall: use cement board there, or at minimum a coat of liquid membrane.
Check the total build-up before you order. Tile plus thinset adds 3/8 to 1/2 inch to the wall. That matters where the tile meets an outlet: plan for a box extender ring so the receptacle and the faceplate sit flat on the tile, because fitting one afterwards means pulling the receptacle back out of a finished wall. If you are not comfortable working on the outlet, that part of the job belongs to an electrician.
Edge treatment
Every backsplash has an exposed edge somewhere: at the end of a run, at the top of the range panel, along a window return. You have three options and they are all bought separately from the field tile.
| Option | Sold as | Estimated cost |
|---|---|---|
| Bullnose or finished-edge tile | By the piece | $3 to $8 each |
| Metal profile (Schluter and similar) | 8 ft lengths | $18 to $35 per length |
| Mitred field tile | No extra material | Labour and a wet saw |
Measure your exposed edges in linear feet before you order. Six feet of exposed edge is eight bullnose pieces or one metal profile, and neither is in the square footage above.
Common mistakes
- Measuring the counter instead of the wall. The tile goes on the wall. A run with a 45 degree corner is longer along the wall than along the counter edge.
- Forgetting the small returns. At 18 inches high, the 9 inch strip beside the fridge is 1.1 square feet and the 12 inch return at the end of a peninsula 1.5, and each one is four cuts.
- Buying one box for a mosaic sheet job. Mosaic sheets are sold by the square foot but cut badly at the edges; add 15%, not 10%.
- Choosing an offset without checking the tile length. Where the side being offset is longer than 15 inches, ANSI A108.02 caps the offset at a third unless the manufacturer says otherwise — the reasoning is in tile waste factor by pattern.
- Grouting to the counter. Treat the joint where tile meets the countertop as a movement joint and fill it with a flexible sealant, not grout; grout in that joint tends to crack.
- Skipping the layout. Centre the field on the range or the sink, not on the wall. The method is in how to lay out a tile floor and it works the same way vertically.