How Much Tile for a Kitchen Backsplash?

Two rectangles, not one wall

A backsplash isn't a wall. It's a long thin band between the worktop and the wall cabinets, plus a taller patch behind the cooker.

Measure it as those two pieces and it becomes easy:

• The main run: 12 ft × 18 in = 18 sq ft
• Behind the cooker: 3 ft × 30 in = 7.5 sq ft
• Minus a window over the sink: −4 sq ft

= 21.5 sq ft

18 inches is the standard, but measure yours

Worktop to the underside of the wall cabinets is 18 inches in most kitchens.

Measure it anyway. 15 and 20 both exist, and on a 12 ft run a 2-inch difference is 2 sq ft — about a tenth of the whole job.

The cooker wall is taller. Behind a range or hob the tile usually runs up to the extractor rather than stopping at cabinet height, so it's a separate rectangle the width of the appliance. On a small job that patch can be a third of the total, and it's the piece most likely to get forgotten because it doesn't fit the pattern of the rest.

Box rounding, not waste percentage, decides the bill

This is the same lesson as the flooring calculator, and it bites harder here because the job is so small.

• Net area: 21.5 sq ft
• Plus 10% waste: 23.7 sq ft
• Tile comes in 10 sq ft boxes → 3 boxes
• What you actually carry home: 30 sq ft

That's 39% more than the area you're covering, and no waste setting you choose will change it. The rounding is in whole boxes.

On a big floor that overshoot disappears into the total. On a backsplash it's most of a box.

Which is fine — keep it

Tile is made in dye lots, and they don't match between production runs. In three years the same product code from the same shop can be visibly different against your wall.

The spare from your own box is the only tile that will ever match.

Store the remainder and the usable offcuts somewhere you'll actually find them, with the lot number written on the box. It's the difference between replacing one cracked tile and retiling the kitchen.

Don't deduct the sockets

This one catches people who've just done a paint calculation, where deducting is right.

You cut the tile around a socket, so the tile is consumed whether the socket is there or not — and the offcut from a socket cut is rarely the right shape to use anywhere else.

Deduct a window. Never deduct a socket.

Deducting small openings is a reliable way to end up one box short on a Sunday.

Waste percentages that reflect reality

• 10% — straight or brick-bond layout, simple rectangle
• 15–20% — diagonal or herringbone, where every perimeter tile is a cut and the offcuts come out the wrong shape
• Less than you'd think for mosaic sheets, because you can cut between the individual tiles rather than through them

Add more if the run turns several corners or wraps an awkward window.

The thing everyone forgets to buy

Edge trim.

The exposed vertical end of a run — and any top edge not meeting a cabinet — needs bullnose, a metal profile, or a matching trim piece. It's sold separately from the tile, it's frequently a different lead time, and it's the single most commonly forgotten item on a backsplash job.

The calculator gives you a starting figure in linear feet so at least it's on the list.

You'll also want more thinset and grout than the tile alone suggests, and a cutter that suits the material — porcelain and natural stone are a very different job from ceramic.

Before you start

• Height measured, not assumed
• Cooker wall measured as its own rectangle
• All boxes from one dye lot, checked on the label
• Trim bought at the same time
• Power off at the consumer unit before removing faceplates
• Layout dry-laid to see where the cuts land
• Starting line marked level — not measured up from the worktop, which never is