Shower Tile Calculator
Tiling a shower? Enter the shower dimensions, tile size, and waste factor to calculate the total tiles needed for walls and floor, plus thin-set mortar quantities for a complete 3-wall surround installation.
Estimate only — not professional advice. Always verify results independently before purchasing materials or beginning work. Terms of Use
What is Shower Tile?
A shower tile calculator determines the number of tiles and bags of thin-set mortar needed to tile a standard 3-wall shower surround (two side walls and one back wall) plus the shower floor. Showers require higher waste factors than standard wall or floor tiling due to the numerous cuts around plumbing fixtures, niches, corners, and the complex geometry of pan-to-wall transitions. The wall area calculation covers three walls: two side walls (each shower depth x tile height) and one back wall (shower width x tile height). The fourth wall is typically open for the shower door or curtain and is not tiled. If your shower has a half-wall, knee wall, or bench, add those areas separately. The tile height is the vertical distance you plan to tile — ceiling height for fully tiled showers (typically 7 to 8 feet), or a lower height if tiling only to a wainscot line. The floor area is simply the shower width multiplied by the depth. Shower floors typically use smaller tiles (2x2 inch or hexagonal mosaic) than walls because the smaller tiles conform better to the sloped shower pan. However, for calculation purposes, the same coverage rate applies regardless of individual tile size — a square foot of coverage requires a square foot of tile material. A 15 percent waste factor is recommended for shower tiling — significantly higher than the 10 percent used for standard wall or floor installations. This increased allowance accounts for cuts at inside corners (every tile at a corner must be cut), cuts around the shower valve, showerhead pipe, and any body spray or niche penetrations, the small pieces wasted when cutting L-shapes around fixtures, breakage of thin wall tiles during cutting, and pattern matching that requires discarding partial tiles. Thin-set mortar (modified thin-set for showers) coverage is approximately 60 square feet per 50-pound bag when applied with a 1/4 x 3/8-inch notched trowel — the standard size for 12-inch tiles. Larger tiles (16-inch and above) require a 1/2 x 1/2-inch notched trowel, which uses more thin-set and reduces coverage to approximately 40 to 50 square feet per bag. Smaller mosaic tiles (mounted on mesh backing) use a 3/16 x 1/4-inch V-notch, which yields approximately 80 to 95 square feet per bag. Shower tile installations require waterproof substrate preparation before tiling. The industry standard is a waterproof membrane (sheet membrane like Kerdi, or liquid-applied like RedGard or Hydroban) over cement board (Durock, Hardiebacker) or a foam board system (Kerdi-Board, GoBoard). Never tile directly over greenboard (moisture-resistant drywall) in a shower — it will fail within a few years as moisture penetrates the grout joints and deteriorates the gypsum core.
How to Calculate
- Measure the shower width (back wall dimension) in feet
- Measure the shower depth (side wall dimension) in feet
- Determine the tile height (how high you will tile — typically 7 ft for full-height, or ceiling)
- Enter the tile size in inches (12x12 is standard for walls, smaller for floors)
- Set the waste factor (15% minimum for showers, 20% if you have many niches or complex layout)
- Review total tile count for ordering — buy extra from the same lot for future repairs
- Note thin-set bag count — modified thin-set is required for shower wet areas
Formula
Wall Area = (2 x Shower Depth x Tile Height) + (Shower Width x Tile Height) Floor Area = Shower Width x Shower Depth Total Tile Area = (Wall Area + Floor Area) x (1 + Waste% / 100) Tiles Needed = ceiling(Total Tile Area / (Tile Size x Tile Size / 144)) Thin-Set Bags = ceiling(Total Tile Area / 60 sq ft per bag) Where tile size is converted from inches to square feet: (size x size) / 144
Example Calculation
3 ft wide x 3 ft deep shower, 7 ft tile height, 12" tile, 15% waste: Wall Area = (2 x 3 x 7) + (3 x 7) = 42 + 21 = 63 sq ft Floor Area = 3 x 3 = 9 sq ft Raw Area = 63 + 9 = 72 sq ft Total Tile Area = 72 x 1.15 = 82.8 sq ft Tiles Needed = ceil(82.8 / (12 x 12 / 144)) = ceil(82.8 / 1) = 83 tiles Thin-Set Bags = ceil(82.8 / 60) = ceil(1.38) = 2 bags
Frequently Asked Questions
How much tile waste should I plan for in a shower?
Plan for 15 percent waste minimum for a standard rectangular shower with a valve and showerhead. Increase to 20 percent if your design includes niches, benches, decorative borders, or diagonal patterns. Herringbone or chevron patterns on shower walls may require 25 percent waste. Always buy all tile from the same production lot — dye lots vary, and replacements purchased later may not match.
What size tile is best for shower walls?
The most popular shower wall tiles are 12x12 inches and 12x24 inches (large format). Larger tiles mean fewer grout lines, creating a cleaner look and easier maintenance. Subway tile (3x6 or 4x12) remains a classic choice. For shower floors, use tiles no larger than 4x4 inches (2x2 or hexagonal mosaic preferred) so they can conform to the sloped shower pan without lippage.
Do I need special thin-set for shower tile?
Yes. Use modified thin-set (polymer-modified) for all shower tile installations. Modified thin-set contains latex or polymer additives that improve bond strength, flexibility, and water resistance compared to unmodified thin-set. For glass tile, large format tile (over 15 inches), and direct-to-membrane installations, use a white polymer-modified thin-set specifically rated for those applications.
How long does thin-set take to dry in a shower before grouting?
Allow modified thin-set to cure for 24 hours minimum before grouting — 48 hours is preferred for shower installations where moisture will be present. In cold or humid conditions (below 60 degrees F or above 80 percent humidity), extend to 72 hours. Do not rush this step — grouting over uncured thin-set traps moisture and weakens the bond. Do not use the shower for at least 72 hours after grouting and sealing.
Should shower tile go to the ceiling?
Tiling to the ceiling is recommended for enclosed showers (glass doors) because steam rises and condenses on the ceiling — an untiled ceiling in a closed shower will develop mold and paint failure quickly. For showers with curtains that are open at the top, tiling to 7 feet (above the showerhead) is sufficient as steam dissipates more readily. Full-height tiling also looks more finished and is easier to clean long-term.