Backsplash tile for a 9 ft run, 15″ high, 2×2″ mosaic in a stacked layout

Tile to buy

12.8ft²

11.3 ft² of wall plus 14% — about 462 × 2×2″ mosaic tiles in stacked

Tile to buy	12.8ft²
Tiles2×2″ mosaic	462tiles
Wall area9 ft × 15″ high	11.3ft²
Waste allowance10% for stacked + 4% for 2 outlets	14%
Outlets to cut aroundNEC wants one within 24″ of any point on the counter	2outlets
Edge trimtwo ends plus the exposed top edge	11.5linear ft
Layoutgrid lines up in both directions — least cutting, least forgiving of a wall out of square	stacked
Heighta short splash — the wall above stays painted	15″

Notes

Backsplash waste is not floor waste. A 15″ strip has far more edge per square foot than the same area on a floor, and every outlet is four cuts and most of a wasted tile. 14% here — 10% for the stacked layout and 4% for 2 outlets.
Grid lines up in both directions — least cutting, least forgiving of a wall out of square.
At 15″ the top edge is exposed and needs finishing: 11.5 linear ft of metal trim or bullnose. A raw cut edge along the top is the single most obvious sign of a DIY backsplash.
Start the layout from the most visible point — usually the centre of the cooktop or the sink — and work outward, so the cut tiles land at the ends where nobody looks.
Buy the whole job in one order. Tile is made in colour lots, and a second box bought three weeks later can be visibly different against the first under kitchen lighting.

Backsplash waste is not floor waste

9 ft × 15″ is 11.3 ft² of wall. Buy 12.8 ft² — 14% over.

That allowance is higher than a floor's for a specific reason. A narrow strip has far more edge per square foot than the same area spread across a floor, and every outlet is four cuts and most of a wasted tile. There are about 2 outlets in a run this long, because the NEC wants one within 24 inches of any point on the counter.

At 2×2″ mosaic that comes to roughly 462 tiles in a stacked layout.

Edge trim: the giveaway

11.5 linear ft. A raw cut edge along the top or at the ends is the single most obvious sign of a DIY backsplash, and it is the one thing you cannot fix later without pulling tile off.

Buy it all at once

Tile is made in color lots. A second box bought three weeks later can be visibly different against the first under kitchen lighting, and kitchen lighting is unforgiving — it comes from directly above and rakes across the wall.

Start from the middle of what people look at

Usually the cooktop or the sink. Work outward from there so the cut tiles land at the ends of the run where nobody looks, rather than dead center behind the range.

Nearby sizes

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