How do I calculate tile for a backsplash?

Multiply backsplash width by height to get square footage, subtract large openings if needed, then add a waste allowance. Divide the adjusted square footage by the coverage per box to find how many boxes to buy.

How much extra tile should I buy for a backsplash?

A 10 percent waste allowance is common for straight layouts. Use 15 percent or more for diagonal layouts, herringbone, many outlets, small cut pieces, or handmade tile with more variation.

Does this calculator include grout and trim?

Yes. The calculator estimates grout weight from tile size, joint width, tile thickness, and backsplash area. It also estimates edge trim pieces from your entered trim length.

Kitchen & bath calculator

Backsplash Tile Calculator

Estimate how many backsplash tiles and boxes to buy, including waste, grout, trim pieces, and material cost.

Tile to buy 35.2 sq ft A 12 ft × 18 in backsplash with 10% extra.

Backsplash area

Total width (feet) Height (inches) Subtract openings (sq ft)

Measure the total run behind the counter. For separate wall sections, add the widths together before entering the number.

Tile and layout

Tile width (inches) Tile height (inches) Waste allowance (%)

Coverage per box (sq ft) Tile price per sq ft ($)

For herringbone, diagonal, handmade, or many-cut layouts, consider 15% waste instead of 10%.

Grout and trim

Grout joint (inches) Tile thickness (inches) Edge trim length (feet)

Trim piece length (feet) Extra trim (%)

How to use this backsplash tile calculator

Enter the total backsplash width and height, choose your tile size, then add the coverage listed on the tile box. The calculator converts the area into square feet, adds your waste allowance, and rounds up to whole boxes.

If your backsplash has multiple sections, measure each width and add them together. Small outlets usually do not need to be subtracted because the cuts still use tile. Subtract only large gaps or areas that will not be tiled.

Useful backsplash planning notes

Standard counter-to-cabinet height: many kitchen backsplashes are about 18 inches tall.
Subway tile example: a 3 in × 6 in tile covers 0.125 square feet before cuts and waste.
Waste allowance: 10% is a common starting point; use more for herringbone, diagonal patterns, or tricky corners.

FAQ

What formula does this calculator use?

Backsplash square feet equals width in feet × height in feet, minus large openings. Tile to buy equals net area × (1 + waste percentage). Boxes equal tile to buy divided by the square feet per box, rounded up.

Should I subtract outlets from the tile area?

Usually no. Outlet cuts often still consume tile pieces, and leaving them in the area helps cover breakage and mistakes. Subtract only larger untiled areas, such as a window or appliance gap.

How accurate is the grout estimate?

It is a planning estimate based on tile size, joint width, thickness, and area. Actual grout use varies by tile edges, surface texture, cleanup, and bag instructions, so round up when buying.