Tile bathrooms.
Tiles and boxes for a shower or tub surround. Calculates three walls plus optional niche and floor, with cut waste built in.
How we calculated this
The calculator treats a shower as three tile surfaces: back wall, two side walls, and an optional floor/ceiling. Standard tub surrounds run 60 inches wide × 32 inches deep × 96 inches tall to the ceiling (or 60-72 inches tall for a tub surround only, without reaching the ceiling). Walk-in showers vary: measure the actual back and side dimensions.
Niches add complexity. A standard 14 × 24 inch niche carved into the back wall: the opening itself (14 × 24 = 336 sq in) is subtracted from the back wall area, then all five interior surfaces (two sides, top, bottom, back) are added. Net: a typical niche adds a small amount of tile (1-2 sq ft) rather than subtracting from the total.
Shower floor (for walk-in showers): add the floor area to the wall total. Drop-in tubs have no tiled floor (the tub is the floor). Many walk-in showers use smaller mosaic tile on the floor for grip, if using different tile on the floor, calculate separately.
Waste factor is 15%: higher than standard floor tile because shower walls have many edges, corners, and fixture cutouts (valve openings, shower head, niche boundaries). Every cut produces scrap that rarely gets reused. Large-format tile (12×24, 24×24) in showers pushes waste up further because bigger scraps are less reusable.
Tiles round up to whole tiles; boxes round up to whole boxes. Buy at least 1-2 extra boxes beyond the calculator's count for future repairs. Shower tile gets chipped by dropped shampoo bottles and razors; matching replacement tile years later is rarely possible.
Not included: backer board (cement board or foam board behind the tile: see drywall calculator for area), waterproofing membrane (recommended: 1 roll covers about 30 sq ft), thinset (1 bag of 50-lb per 40-50 sq ft), grout (see grout calculator), niche trim pieces, and fixtures (shower head, valve, soap dish).
A shower is five surfaces, not one
Tiling a shower means covering a back wall, two side walls, a floor, usually a curb, and often a niche, and each of those wants its own number. The walls carry most of the square footage. The floor is small but takes different tile. The curb and niche are tiny in area and consume a surprising amount of time because almost every piece is a cut. Add them separately or the order comes up short.
The calculator above takes your alcove dimensions and returns shower wall tile and shower floor tile quantities separately, with waste applied. This page covers how the areas break down, why the floor gets small tile and the walls do not, the slip resistance number that governs wet floors, what a tile-ready pan changes, and the waterproofing decision that matters more than any of it.
How we calculated these numbers▾
Area math is straightforward geometry; the judgment is in waste and method. Installation practice follows the TCNA Handbook wet area methods, waterproofing membranes are specified to ANSI A118.10, and floor slip resistance follows ANSI A137.1, which sets a wet dynamic coefficient of friction of 0.42 as the threshold for level interior wet areas. Shower compartment size and slope requirements come from IRC Section P2708 and the plumbing code adopted locally.
Shower sizes and the tile they need
Wall area to 96 in | Floor area | With 10% waste | |
|---|---|---|---|
| 32 x 32 in corner | 64 ft² | 7 ft² | 78 ft² total |
| 48 x 32 in alcove | 75 ft² | 11 ft² | 95 ft² total |
| 60 x 32 in alcove | 82 ft² | 13 ft² | 105 ft² total |
| 60 x 36 in alcove | 88 ft² | 15 ft² | 113 ft² total |
| 72 x 42 in walk-in | 101 ft² | 21 ft² | 134 ft² total |
Wall area assumes tiling to 96 inches, the common full-height finish. Tiling to 72 inches instead cuts wall area by about a quarter.
Two notes on reading that. The IRC requires a shower compartment to have at least 900 square inches of floor area and to fit a 30 inch circle, which is why 32 by 32 is the practical minimum and why anything smaller is a code problem rather than a tight squeeze. And a niche adds far more work than its four square feet suggest: it has a floor, a back, two sides, a top, and often a bullnose edge, all in small cut pieces.
The best tile for a shower floor
A shower floor slopes a quarter inch per foot toward the drain, and it does so in every direction, which makes it a shallow cone rather than a plane. Tile has to follow that shape. Mosaic sheets at 2 inches and under articulate across the slope because each small piece can sit at a slightly different angle. Large format tile cannot: it bridges the curve, leaves voids under the middle, and holds standing water at the low edge. That is the entire reason showers pair big shower wall tile with small shower floor tile, and it is a physical constraint rather than a style convention.
Slip resistance is the second constraint. ANSI A137.1 defines a wet dynamic coefficient of friction, DCOF, and 0.42 is the threshold for level interior areas expected to be walked on wet. Manufacturers publish the number on the spec sheet. Polished porcelain, which looks superb on a wall, generally fails it, and a polished tile on a shower floor is a genuine hazard rather than a preference. The extra grout lines in a mosaic help here too, which is a second argument for the same answer.
Walls | Floor | |
|---|---|---|
| Typical size | 3x6 subway up to 12x24 | 1x1 or 2x2 mosaic |
| Finish | Polished, matte, or glossy all fine | Matte or textured, DCOF 0.42 or higher |
| Material | Porcelain, ceramic, glass, stone | Porcelain or unglazed mosaic |
| Grout joints | 1/16 to 1/8 in | 1/16 to 1/8 in, far more of them |
| Why | Flat plane, no traffic, appearance leads | Compound slope plus wet footing |
What belongs where. The best tile for a shower floor is almost always a mosaic under 2 inches with a published DCOF at or above 0.42.
Shower pans: mud bed or tile-ready
Under the floor tile sits a pan, and there are two ways to build one. The traditional method is a mortar bed sloped by hand over a membrane, which is inexpensive in materials, entirely dependent on the installer, and the source of most old shower failures. The modern method is a pre-sloped foam shower pan, sold as a tile ready shower pan or shower base for tile, with the slope moulded in and a bonded waterproofing sheet over the top.
A tile ready shower pan costs $200 to $600 against perhaps $60 of mortar, and they are worth it for most people. The slope is correct by manufacture, the waterproofing is a tested system rather than a field assembly, and the whole thing goes in during one afternoon instead of two days with a cure between. They come in standard sizes matching the alcove dimensions in the table above, with center, offset, or linear drain options. The tile quantity does not change; what changes is whether the substrate under it is reliable.
Waterproofing is the part nobody sees
Cement board is not waterproof. This surprises people, and it is the single most consequential misunderstanding in shower construction. Backer board is a stable substrate that tolerates moisture; the waterproofing is a separate layer, either a sheet membrane bonded over the board or a liquid-applied membrane rolled on in two coats to a specified thickness. Both are specified to ANSI A118.10, and both are the reason the shower does not rot the framing behind it in six years.
The corollary matters for the tile order: seams, corners, and the curb all need treatment before any tile goes on, and the niche needs waterproofing wrapped into it. If a quote does not name a waterproofing system, that is the question to ask before discussing tile at all. Tile and grout are water resistant, not waterproof; water passes through grout continuously and the membrane behind is what catches it.
A 60 by 32 inch alcove replacing an old fiberglass surround. Walls tiled to 96 inches in 3 by 6 subway laid in running bond, floor in 2 by 2 porcelain mosaic, plus a 14 by 24 inch niche and a tiled curb.
Walls: 82 ft². Floor: 13 ft². Niche and curb: about 6 ft² of surfaces, nearly all cuts. Subway at 10 percent waste means ordering 97 ft² of wall tile; the mosaic at 10 percent means 15 ft², which is four or five sheets more than the bare number because sheets come in fixed sizes. At $4 per square foot for the subway and $12 for the mosaic, tile runs about $570. The tile-ready pan adds $380, the waterproofing system about $250, and thinset, grout, and trim another $200. Materials land near $1,400, with the tile itself less than half of it, which is the part homeowners consistently misjudge.
Composite illustration based on typical project dimensions, regional contractor pricing, and 2026 material costs. Not a specific real project.
Where shower tile jobs go wrong
Ordering wall and floor as one number. They are different products at different prices with different waste. A combined square footage buys the wrong quantity of both.
Large tile on the shower floor. Covered above, and it keeps happening because the plank looks continuous with the bathroom floor. It cannot follow the slope, and the result is ponding and eventually a failed installation.
Forgetting the niche and curb are all cuts. Six square feet of surfaces can consume fifteen square feet of tile once every piece is trimmed with a bullnose or mitred edge. Bump the waste factor rather than the area.
Buying in two orders. Tile is made in dye lots and shade varies between them. In a space where every wall is within arm's reach, a lot mismatch reads instantly. Order the whole job at once and keep the leftovers for future repairs.
The rest of the bathroom
Shower tile is one line in a bathroom budget. Grout for all those joints runs through the grout calculator, the vanity on the opposite wall is a vanity calculator question, and backer board quantities come from the drywall calculator. If the drain or supply lines are moving, size them with the drain pipe calculator.
Measure each wall, add the floor separately, run it through the calculator above, and order both in one go. The tile is the easy part; what goes behind it is what lasts.
Frequently asked
How many tiles do I need for a standard shower?
For a standard 60 × 32 × 96 inch tub surround (3 walls only, to ceiling) using 12×24 tiles with 15% waste, you need about 60 tiles or 8 boxes of 8. Walk-in showers with a floor need 10-15% more tile. Include a niche adds another ~2 ft² of tile.
Should I use the same tile on floor and walls?
You can, but slip resistance is a concern on wet floors. For shower floors, use tiles with DCOF ≥ 0.42 (slip rating) or switch to small mosaic tile (under 2 inches) where grout lines provide grip. Walls don't have this concern. Many showers pair large wall tile with small mosaic floor tile for this reason.
Why is shower waste 15% instead of 10%?
Showers have more edges, corners, and cutouts than floors. Fixture penetrations (shower head, valve, tub spout, niche edges) each require precise cuts that leave unusable scraps. Large-format wall tile makes this worse because each cut wastes a bigger piece.
What about the ceiling?
Most showers don't tile the ceiling: use moisture-resistant drywall with mildew-resistant paint instead. If you do tile the ceiling (for a steam shower or luxury finish), calculate the ceiling area separately (back wall width × side depth) and add to the total. Ceiling tile is harder to install and requires special thinset.
How big should my niche be?
Standard 14 × 24 inches (the space between standard studs at 16" on center, minus framing). Smaller niches (8 × 12) fit between 2×4 framing without disrupting studs. Multiple small niches are sometimes preferable to one large niche for organizing shampoo, conditioner, soap.
What about curbs and benches?
Not automatically calculated. A standard curb (the barrier at the shower entrance) is about 6 × 4 × 36 inches: adds ~1 ft² of tile. A built-in bench is 15-18 × 48 inches typically: adds 3-5 ft². Add these to your total manually and bump the calculator's dimensions.
Do I need waterproofing behind tile?
Yes: modern standard. Cement board alone is not waterproof. Use a sheet membrane (like Schluter Kerdi) or liquid-applied waterproofing (like RedGard) over the backer board. Standard shower areas typically need 1 roll (40 sq ft) of sheet membrane or 1-2 gallons of liquid.
Can I do this over an existing tub surround?
Not directly on existing tile (old tile must come off first). If removing old tile, inspect the backer: water damage behind old shower tile is very common. Plan to replace the cement board, not just the tile. Factor 1-2 extra days and $200-500 in backer/waterproofing materials on top of new tile.
Sources
- TCNA Handbook: Wet Area Installation Methods - The B and W series methods governing shower walls, pans, and waterproofing assemblies
- ANSI A118.10: Load Bearing Bonded Waterproof Membranes - The specification a shower waterproofing membrane must meet
- ANSI A137.1: Ceramic Tile Specification and DCOF - Defines the 0.42 wet dynamic coefficient of friction threshold for wet floor tile
- IRC 2021, Section P2708: Shower Compartments - The 900 square inch minimum floor area and 30 inch circle requirement
- Schluter Systems: Shower Construction Guide - Bonded waterproofing and pre-sloped pan assembly practice
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