Shower Tile & Trim Calculator
Estimate the wall tile and edge trim for a three-wall shower surround — tile count with waste, plus the bullnose or trim length for exposed edges.
How it works
Wall area = (back + 2 × side) × height · Tiles = ⌈area × (1 + waste%) ÷ tile face area⌉ · Trim = perimeter + 2 × height
A standard shower surround tiles three walls, so the area is the back wall plus both side walls multiplied by the tile height. Dividing by each tile’s face area gives the raw count, then a waste allowance (usually 10% for a straight layout, more for diagonal or mosaic work) covers cuts and breakage. The finished edges — the top course and the two vertical edges at the open front — are where you use bullnose or edge trim rather than raw cut tile.
Worked example
A 3 ft back wall with two 3 ft side walls, tiled 6 ft high, is (3 + 6) × 6 = 54 sq ft. With 10% waste that is 59.4 sq ft; in 3"×6" subway (0.125 sq ft each) that is about 476 tiles, plus 9 + 12 = 21 ft of edge trim.
Frequently asked questions
How much tile waste should I allow?
About 10% for a simple straight or brick layout, and 15–20% for diagonal patterns, small mosaics, or a room with many cuts around niches and valves. Buying from one batch also protects against shade variation between production lots.
What is edge trim or bullnose for?
Field tiles have raw cut edges. Bullnose (a tile with one finished rounded edge) or a metal/PVC trim profile caps the exposed top course and the vertical edges at the shower opening so no sharp, unglazed edge shows.
Does this include the floor or niche?
No — this estimates the three wall faces only. Add the shower pan/floor and any niche or bench separately, and subtract large fixed openings like a window if you want a tighter number.
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This calculator is for educational purposes. Double-check important results before acting on them.