What is the Shower Tile Calculator?
The Shower Tile Calculator estimates how many wall tiles you need to cover the walls of a standard shower or shower-tub surround. It adds the area of the back wall and any side walls, converts that into a tile count based on your chosen tile size, and adds a waste allowance for cuts, breakage, and future repairs. This works for any country and any unit as long as you stay consistent — the examples use inches.
How to use it
Enter the shower wall height, the back wall width, and the width of each side wall. Choose how many side walls you are tiling (2 for a typical alcove, 1 for a corner setup, or 0 for a single feature wall). Then enter your tile width and height and a waste percentage. Most installers use 10% waste, or 15% for diagonal layouts and patterned tile.
The formula explained
First the calculator finds the total tiling area:
$$A_{wall} = h \times (W_{back} + n \times W_{side})$$where \(h\) = wall height, \(W_{back}\) = back wall width, \(W_{side}\) = each side wall width, and \(n\) = number of side walls. It then divides by the area of one tile \(w_t \times h_t\), multiplies by the waste factor \((1+w)\), and rounds up:
$$N = \left\lceil \frac{A_{wall}}{w_t \times h_t} \times (1 + w) \right\rceil$$
Worked example
A 96 in tall alcove shower with a 60 in back wall and two 36 in side walls, using 12 × 12 in tiles and 10% waste:
$$A_{wall} = 96 \times (60 + 2 \times 36) = 96 \times 132 = 12{,}672\ \text{in}^2$$$$N = \left\lceil \frac{12{,}672}{144} \times 1.10 \right\rceil = \left\lceil 88 \times 1.10 \right\rceil = \lceil 96.8 \rceil = 97\ \text{tiles}$$That is 88 sq ft of wall area, needing 97 tiles with waste included.
FAQ
Does it subtract the niche or window? No — to keep estimates safe it tiles the full rectangle. Small openings are usually covered by the waste allowance.
How much waste should I add? Use 10% for straight layouts, 15% for diagonal or herringbone, and up to 20% for mosaics or intricate patterns.
Can I use metric units? Yes. Enter all dimensions in cm instead of inches; the tile count stays correct, though the area shown assumes inches-to-square-feet conversion.
