Shower Tile Calculator
Calculate exactly how much tile, thinset mortar, and waterproofing membrane you need for a shower remodel. Automatically applies industry-standard waste factors based on your layout pattern and large-format tile (LFT) constraints.
How to calculate materials for a shower remodel
Map the wall geometry
Measure the exact width of the back wall and the depth of the side walls in inches. Determine your tile height—while older showers stopped at 72 inches, modern standards run the tile all the way to the 96-inch ceiling to prevent drywall moisture damage above the showerhead.
Select your tile pattern
The pattern drives your waste factor, not just the square footage. A standard straight stack wastes about 10%. An offset or running-bond pattern creates more edge cuts (15%). Diagonal and herringbone patterns throw away a cut at every single perimeter edge, requiring 20% waste or more.
Account for Large Format Tile (LFT)
Per ANSI A108.02, any tile with a single edge over 15 inches is "large format." LFT tiles are slightly crowned in the middle from kiln baking. They require a mandatory 5% extra waste allowance and force contractors to use medium-bed mortar instead of standard thinset to prevent "lippage."
Calculate the wet-wall assembly
Tile and grout are not waterproof. The calculator automatically computes how many gallons of liquid waterproofing membrane (like RedGard) you need to coat the cement board behind the tile, as well as the 50lb bags of mortar required for 95% wet-area trowel coverage.
Frequently asked questions
What materials actually go behind shower tile?
Tile and grout are porous and not inherently waterproof. A modern wet-wall assembly consists of wood framing, covered by cement board (never standard drywall), which is then fully coated in an ANSI A118.10 waterproofing membrane (either a liquid like RedGard or a sheet like Kerdi). The tile is then set into 95%-coverage thinset mortar on top of that membrane.
Why do large format tiles (12x24) need more waste?
Any tile with an edge over 15 inches is classified as a Large Format Tile (LFT). Because a single miscut on a 24-inch tile throws away a massive amount of square footage, a mandatory 5% extra waste is added. Furthermore, LFTs cannot be laid in a 50% brick pattern; they are limited to a 33% maximum offset to prevent the crowned center of the tile from sticking out past the flat edge of the adjacent tile (a defect known as lippage).
Can I use the same tile for the walls and the shower floor pan?
Generally, no. Shower pans must slope downward toward the drain. Large wall tiles (like 12x24s) cannot bend to follow the contours of a funnel-shaped floor pan without severely cracking or "lipping." Unless you are using an advanced envelope cut or a linear trench drain, shower pans require small mosaic tiles (typically 2x2 or 4x4) that can conform to the slope.
How much mortar (thinset) do I need?
Showers are classified as wet areas, meaning ANSI A108.5 rules demand 95% mortar coverage behind the tile. You cannot use the "dot and dab" spot-bonding method. To achieve 95% coverage, you must use an appropriately sized trowel and often "back-butter" the tiles. Expect a 50lb bag of thinset to cover roughly 70 sq ft for small tile, or just 40 sq ft for large-format tile using a 1/2" notch trowel.
About this calculator
This Shower Tile Calculator takes the guesswork out of ordering materials by adhering strictly to TCNA (Tile Council of North America) and ANSI A108 guidelines for wet-area installations.
The calculation engine utilizes the following professional logic:
Net Surface Area = Wall Area + Pan Area (If selected) + 10 sq ft curb allowance
Base Waste Factor = Straight (10%) | Offset (15%) | Herringbone (20%)
LFT Modifier = +5% waste if Tile Length or Width ≥ 15 inches
Total Order Sq Ft = Net Area × (1 + Waste Factor)
Thinset Coverage = 1 Bag per 70 sq ft (Standard) or 40 sq ft (Large Format Tile)
Base Waste Factor = Straight (10%) | Offset (15%) | Herringbone (20%)
LFT Modifier = +5% waste if Tile Length or Width ≥ 15 inches
Total Order Sq Ft = Net Area × (1 + Waste Factor)
Thinset Coverage = 1 Bag per 70 sq ft (Standard) or 40 sq ft (Large Format Tile)
A note on shower niches: Adding a shampoo niche does not significantly increase your square footage, but it does dramatically increase your linear feet of bullnose tile or metal Schluter edging. Always buy extra trim pieces to account for the miters required around a niche or window.