A Worked Example: Backsplash Tile for a Kitchen

A kitchen backsplash measured in three segments needs 220 pieces of 3 in × 6 in subway tile. The net area is 25.0 sq ft, a 10% cut allowance brings the order to 27.5 sq ft, and boxes of 55 pieces give exactly 4 boxes. This page works the example line by line, then runs three independent checks on the result.

What does the example kitchen measure?

The kitchen has two standard wall runs and one above-range zone where tile climbs to the hood. Each run is measured as a rectangle in inches, following the backsplash measuring guide. The standard band is 18 in from countertop to the underside of the wall cabinets, matching the NKBA cabinet-planning clearance.

Only the in-boundary portion of the window is deducted. Tile wraps the window edges, but a full deduction of the window area inside the boundary is the right planning figure.

Four outlets and one switch sit inside the tile band. They are recorded as cut locations on the layout plan, not as area deductions. Each outlet costs one cut tile in practice, and the cut allowance covers that waste.

Net area = sum of segment areas − openings inside the tile boundary

Square feet = square inches ÷ 144

How do you turn the measurements into a tile count?

Each 3 in × 6 in subway tile covers 18 sq in, which is 0.125 sq ft. Eight pieces cover one square foot exactly. The Tile Calculator accepts the same net area as a checked known area.

First compute the net piece count without any allowance: 25.0 ÷ 0.125 = 200 pieces. This number stays on the record beside the area it came from.

Next apply the cut allowance. The layout is a straight brick pattern on a rectangular wall, so the allowance is 10%. The Tile Association, the UK tile trade body, advises 10% extra for breakages and cutting on straightforward work, and notes that larger tiles may need more.

Order area = net area × (1 + allowance % ÷ 100)

Order area = 25.0 × 1.10 = 27.5 sq ft

Pieces = 27.5 ÷ 0.125 = 220

The allowance applies to the checked net area. A percentage added to an unmeasured wall hides measurement error instead of covering cuts.

How does the tile count become a box order?

The supplier sells this tile in boxes of 55 pieces. Box coverage comes from the box contents, not from the nominal tile size: 55 × 0.125 = 6.875 sq ft per box. Check the printed coverage on your own box, because box counts differ by product.

Boxes = pieces ÷ pieces per box = 220 ÷ 55 = 4.0

Round the box count up. Here 4.0 is already whole, so the order is 4 boxes, delivering 220 pieces = 27.5 sq ft. Keep the unrounded values on the record: net 25.0 sq ft, allowance 10%, 220 pieces, 4 boxes.

How do you verify the order?

Three independent checks confirm the result. Run at least one before ordering.

Check 1: re-measure in metric units

Convert every segment to millimetres and compute the net area in square metres. The same kitchen must give the same area in both unit systems.

Net = 3600 sq in × 645.16 mm²/sq in = 2,322,576 mm² = 2.322576 m²

25.0 sq ft × 0.09290304 m²/sq ft = 2.322576 m²

Both paths land on 2.322576 m². A mismatch means a conversion error in one path, not a problem with the wall.

Check 2: order from box coverage instead of piece count

Divide the allowed area by the box coverage and round up. This path never counts pieces.

Boxes = 27.5 ÷ 6.875 = 4.0 → 4 boxes

The box-coverage path agrees with the piece path. A mismatch means the box coverage or the piece count is wrong.

Check 3: test the allowance at the box boundary

Re-run the order with a 15% allowance, as for a herringbone layout or a wall with many outlet cuts. The ordering guide uses 15% for diagonal or busy layouts.

25.0 × 1.15 = 28.75 sq ft → 28.75 ÷ 0.125 = 230 pieces → 230 ÷ 55 = 4.1818 → 5 boxes

The same net area orders 5 boxes under a 15% allowance. The allowance choice crosses a box boundary here, which is why the record keeps the net area, the percentage, and the rounded counts together: the decision stays reproducible.

What changes the answer?

• A herringbone or diagonal layout uses 15%, not 10%, because angled cuts turn more tile into offcuts. Check 3 shows the extra box this buys.
• Full-height sections add area. Measure each run at its own height instead of averaging the cabinet gap across the kitchen.
• A different tile size needs its own piece area and its own box count from the printed coverage. The 8-pieces-per-square-foot figure applies to 3 in × 6 in tiles only.
• Mosaic sheets are ordered by sheet coverage, not by piece math. Use the sheet size and the box's sheet count.
• Grout joints are ignored in the area method. For 3 in × 6 in tiles the effect on the piece count is negligible at planning precision, so the fixture keeps the geometry simple.

Common mistakes this example avoids

• Measuring one overall wall length and missing the taller range zone and the window deduction.
• Deducting outlets as area instead of recording them as cut locations, which understates the cuts the allowance must cover.
• Adding the allowance to a rough area before the segments are measured.
• Rounding the segment areas before adding them, which hides fractions that accumulate across runs.

The backsplash tile mistakes guide covers these in full, and the tile waste allowance guide explains how to set the percentage for other layouts.