Measure a kitchen backsplash, subtract non-tiled openings and estimate tile or sheet quantities and boxes.
Quick answer: Backsplash tile area = total run length × tiled height − non-tiled openings. A 10 ft run at 1.5 ft high is 15 sq ft; subtracting 1 sq ft and adding 10% waste gives 15.4 sq ft to buy. That is 16 sheets at 12 × 12 inches, or two boxes covering 10 sq ft each.
Switching units converts existing numeric inputs.
ft
Sum runs only when they share the same height.
ft
sq ft
Count each non-tiled opening once. Niche returns are additional area.
in
in
sq ft
%
Net tile area
15.00 sq ft
Gross 15.00 minus openings 0
Buy area with waste
16.50 sq ft
Whole tiles
17
Area estimate; layout can require more pieces
Whole boxes
2
At 10 sq ft per box
Counts are area-based estimates, not a cut-layout optimizer. Add niche returns, benches, curbs and ceilings separately. For different wall and floor tiles, calculate separate orders. Openings must not overlap or be counted twice.
A backsplash calculator turns a rectangular kitchen wall measurement into an area-based tile order. Measure only the height to be tiled, not the full wall to the ceiling unless that is the intended finish. Runs of equal height can be combined into one length. For mixed heights, such as a range splash reaching above nearby cabinets, calculate the sections separately and add their areas. The piece estimate uses either an individual tile or an entire mosaic sheet, while the box estimate uses the manufacturer's printed coverage.
Common uses for Backsplash Calculator
Estimate subway tile for a straight countertop run
Count mosaic sheets without counting each small chip
Subtract a large window from the tiled area
Plan separate short and full-height backsplash sections
Measure the actual tiled height
Enter US wall dimensions in decimal feet: an 18 inch backsplash is 1.5 feet, not 18 feet. Tile or sheet dimensions are entered separately in inches. Metric wall dimensions use metres and tile dimensions use millimetres. The unit selector converts existing numeric values so you can compare the same project without retyping it.
Openings and mixed-height sections
Subtract only surfaces that will not receive tile. Count each opening once and avoid overlapping deductions. Small outlet cuts can consume almost a full tile despite removing little area, so a waste allowance and layout check remain necessary. For a different-height range section, calculate it separately rather than multiplying the entire length by the maximum height.
Mosaic sheets and packaging
Choose sheet mode and enter the outside dimensions of the mounted sheet, not the tiny tile chips. Sheet coverage can differ from its nominal size because of interlocking edges and joint spacing; use the printed box coverage for the final purchase. Piece and box counts are independent area estimates, not a nesting or cut-reuse plan. Herringbone and many outlet cuts can need a larger allowance.
Frequently Asked Questions
How do I calculate an 18 inch backsplash?
In US mode enter 1.5 feet as the height. Multiply by the total same-height run length, subtract non-tiled opening area and add your cutting allowance.
Do I enter mosaic chip size or sheet size?
For sheet counts, select mosaic sheets and enter the whole sheet dimensions. Use actual printed coverage per box for the purchase estimate.
Should I subtract outlets?
You may subtract the measured non-tiled area once, but small outlet cuts do not necessarily reduce purchased pieces. Retain a cutting allowance and check the layout.
Does this include grout and mortar?
No. The result is tile area, pieces and boxes. Use the linked grout and thinset calculators for those separate materials.