How Much Subway Tile Do I Need for a Backsplash?

By Real Kitchen Editors

November 02, 2026

The short answer: measure the width and height of each part of the wall in inches, multiply, add the parts together and divide by 144. That’s your square feet. Then add 15% for cuts and breakage (20% for herringbone) and round up to whole boxes.

For a typical 10-foot wall with an 18-inch backsplash and the tile run up to the hood behind the stove, that comes to 17.5 square feet. With the extra, buy 21 square feet of tile. The steps below show the math.

Step 1: Measure each part of the wall

Sketch the wall on paper first. Most backsplashes break into a few simple rectangles:

Each run of wall, from the counter up to the bottom of the wall cabinets. Include the width of the stove in this run.
Behind the stove, if the tile goes higher there, up to the hood.
Beside a window, if the tile runs up to the window frame.

For each rectangle, measure the width and the height in inches. Fireclay Tile, a tile maker, says to write the numbers down and always round up. We’d also measure in two or three spots, because walls and cabinets are rarely perfectly even, and use the biggest number.

Take out large openings like a window. We leave the outlets in: they’re small, and the tiles you cut around them are mostly waste anyway.

Step 2: Turn inches into square feet

Tile is sold by the square foot. For each rectangle, multiply width by height to get square inches, then add them all up and divide by 144 (the square inches in one square foot).

A worked example:

The whole wall, 120 inches wide including a 30-inch stove, by 18 inches high = 2,160 square inches.
Behind the stove, the extra strip from the cabinet line up to the hood: 30 inches wide by 12 inches high = 360 square inches.
Total: 2,520 square inches. Divide by 144 = 17.5 square feet.

Step 3: Add the extra

You’ll lose tile to cuts at the ends of rows, around outlets and to the odd broken piece. Fireclay recommends ordering 15% to 20% extra in general, and at least 20% for herringbone, because every row ends in angled cuts.

Classic brick or stacked layout: add 15%. In the example, 17.5 × 1.15 = 20.1, so round up to 21 square feet.
Herringbone: add 20%. In the example, 17.5 × 1.2 = 21 square feet. The rounding happens to land on the same number here. On a 30-square-foot wall it wouldn’t: 35 square feet with 15% extra, 36 with 20%.
Chevron: no source we found gives a figure, so we’d use the herringbone number.

Buy it all at once. Fireclay warns that it can’t promise an exact color match between separate orders, and colors can shift between batches of other tile too. Keep a few spare tiles after the job, in case one ever cracks.

Step 4: Turn it into boxes, tiles and trim

Every box lists how many square feet it covers. Divide your total by that number and round up. If a box covers 5 square feet, 21 square feet needs 4.2 boxes, so buy 5. Coverage varies a lot from one tile to the next, so always check the label of the tile you’re buying.

If the tile is sold by the piece, here’s roughly how many it takes to cover a square foot. Use the count printed on the box when there is one, since many tiles are a little smaller than their name.

Tile size	About this many per sq ft
3 x 6 in (classic)	8
2 x 8 in (skinny)	9
4 x 12 in (long)	3

Trim. For edge trim or rounded tile on exposed ends, measure the length of every edge that needs it in feet. Fireclay says to add 15% and round up to the next whole foot.

Grout and adhesive. How much you need depends on the tile size and the gap. Use the coverage chart on the bag or the maker’s online calculator, and buy for the square feet you just worked out.

What else to buy

Here’s the short version of Lowe’s tools and materials list for a 3-by-6 subway backsplash.

To prep the wall: sandpaper or a sanding block (100 to 150 grit), TSP cleaner, joint compound to fill dents, and tile primer if the wall is bare drywall or freshly patched.
To stick the tile: thin-set mortar (a tile adhesive you mix with water) and a notched trowel. Use the notch size on the mortar bag.
To space it: tile spacers. Lowe’s sets 3-by-6 tile with 1/16-inch gaps.
To hold the first row behind the stove: a straight 1x4 board and screws, as a temporary ledge where there’s no counter.
To grout it: grout, a rubber grout float, sponges and two buckets. Not sure of the color? See what color grout to use.
To finish the edges: caulk and a caulk gun for the gap along the counter and cabinets, plus the edge trim from Step 4.
To cut it: a snap tile cutter for straight cuts, and tile nippers or a rotary tool for notches around outlets.
To protect the room: painter’s tape and paper for the counter, a long level, and spacers for the outlet boxes.
To stay safe: safety glasses, nitrile gloves and an N95 mask. That’s what CUSTOM’s grout data sheet calls for, because wet cement grout and mortar can cause severe skin burns and eye damage, and the dust contains silica. The sheet warns you can’t rely on pain to tell you it’s burning, so wash it off your skin right away.

Turn off the power to the outlets before you take the covers off.

How long it takes

Spread the job over at least three days, longer if you prime or seal:

Day 1: prep the wall and set the tile. If you prime, let the primer dry first, as its label says.
Day 2: grout. Lowe’s lets the mortar dry 24 hours first, and CUSTOM says its cement grout needs the adhesive to cure 24 to 48 hours, unless you use a fast-setting mortar.
Day 3: caulk the edges. Lowe’s caulks once the grout has cured, about a day later.
Day 4 or later, if you seal: sealer makers like Aqua Mix say to let new grout dry at least 48 hours first.

If you’d rather skip mortar, grout and waiting, see whether peel-and-stick backsplash works and our picks of the best peel-and-stick tile.

Common questions

Do I need to tile behind the fridge or the stove?

Only where it shows. Nobody sees the wall behind a fridge, so most people stop the tile at the fridge’s edge. Behind a freestanding range, the wall above the cooktop shows, so tile that. The part hidden behind the range itself can be left bare.

Should I return the leftover tile?

Return any full, unopened boxes if the store allows it, but keep one box or a dozen loose tiles. If a tile ever cracks, a match from the same batch is the easiest fix. You can also use spares to test grout colors on a scrap board before you start.

Does a bigger tile mean buying less?

No. You need the same square feet of tile whatever the size. Bigger tiles do mean fewer pieces to set and fewer grout lines to clean. See how size changes the look in our subway tile backsplash ideas.