How To Calculate Tile For A Shower
By The Calcumatix Team Reviewed by Calcumatix Editorial Review 4 min read
Quick Answer
To calculate tile for a shower, measure the width and height of every wall, niche, and curb in inches. Multiply width by height for each section to find square inches, then divide by 144 to convert to square feet. Add all the square footage together. Multiply the total by 1.15 to add a 15% waste factor for cuts and breakage. Divide that final number by the square footage listed on one box of your chosen tile, and round up to the nearest whole box.
Tiling a shower requires more precision than tiling an open floor. You are working with vertical surfaces, inside corners, outside corners, recessed niches, and raised curbs. Every edge and corner requires cuts, which means you will waste more material than usual. Running out of tile halfway through a shower build is a disaster because the next batch you order might come from a different dye lot and slightly mismatch in color. This guide walks through the step-by-step procedure to measure your shower surfaces, calculate square footage, apply the correct waste factor, and find exactly how many boxes to order.
How To Measure And Calculate Shower Square Footage
Do not try to measure the shower as one single giant box. Measure it as a series of flat rectangles. You must measure the exact areas you intend to tile. If you are tiling to the ceiling, measure to the ceiling. If you are tiling a wainscot, only measure halfway up.
Step by step:
- Measure the width and height of the back wall in inches.
- Multiply width by height, then divide by 144. This gives you the square footage for the back wall.
- Repeat the process for the left wall and the right wall.
- Measure the interior sides, back, top, and bottom of any built-in niches. Add them together.
- Measure the top, inside, and outside faces of the shower curb. Add them together.
- Add the square footage of the walls, niches, and curb together to find the raw total square footage.
Note: Do not subtract the area for small plumbing cutouts (like the showerhead or mixing valve). The tile you “save” there will be consumed by the intricate cuts required to go around those pipes.
Worked example: Inputs: Back wall 60 inches wide by 96 inches high. Two side walls 36 inches wide by 96 inches high each. Curb and niche total 5 square feet. Step 1 (back wall area): 60 × 96 = 5,760 Step 2 (convert to sq ft): 5,760 / 144 = 40 Step 3 (side wall area): 36 × 96 = 3,456 Step 4 (convert to sq ft): 3,456 / 144 = 24 (per side wall) Step 5 (raw total): 40 + 24 + 24 + 5 = 93
Raw total area: 93 square feet
This is the exact surface area of the shower. Do not order 93 square feet of tile, or you will run out before you finish. You must add a waste factor.
How To Calculate The Tile Waste Factor For A Shower
Waste factor accounts for tiles you must cut to fit against a wall, tiles broken during transit, and tiles broken during the cutting process. Because showers have so many corners, they require a higher waste factor than a standard floor.
Standard waste percentages:
- 10% to 15%: Use for standard grid patterns or stacked subway tile.
- 15% to 20%: Use for offset running bond (brick) patterns or when using large-format tiles in a small shower.
- 20% to 25%: Use for diagonal patterns, herringbone patterns, or natural stone (which may have natural flaws you need to cut around).
To apply the waste factor, convert the percentage to a decimal (15% becomes 0.15), add 1 to it (1.15), and multiply by your raw square footage.
Worked example: Inputs: Raw total area 93 square feet. Chosen pattern requires a 15% waste factor (1.15). Step 1: 93 × 1.15 = 106.95
Total tile required: 107 square feet (rounded to the nearest whole number)
How To Calculate The Number Of Tile Boxes To Order
Tiles are rarely sold by the individual square foot. They are sold in boxes, and the square footage per box varies wildly depending on the size and thickness of the tile.
To find the final order quantity, look at the manufacturer’s label to find the coverage area per box, then divide your total required square footage by that number.
Worked example: Inputs: Total tile required 107 square feet. Chosen tile provides 12.5 square feet per box. Step 1: 107 / 12.5 = 8.56
Final order amount: 9 boxes (always round up to the nearest whole box)
Ordering 9 boxes ensures you have enough material to finish the job, plus a few spare tiles to keep in the garage in case a tile cracks a few years from now. Use the Shower Tile Calculator to calculate your exact wall dimensions, niches, and box conversions automatically. See the construction calculators hub for related tiling and material tools.
Sources and References
Frequently asked questions
Do I need to calculate trim pieces separately?
Yes. Trim pieces (like bullnose, pencil tile, or Schluter metal edging) are sold by the linear foot, not the square foot. To calculate trim, measure the length of all the outside corners, the exposed edges of the shower enclosure, and the front lip of the niches and curbs in inches. Divide by 12 to get linear feet, then add a 10% waste factor for mitering the corners.
How do I calculate tile for a sloped shower pan?
Shower pans (the floor) require their own separate calculation. Measure the width and depth of the shower pan area. Multiply them to get the square footage. Add a 15% waste factor because of the intricate diagonal cuts required to follow the slope down to the drain. Note that shower pan tiles must be small (usually 2x2 inches or smaller mosaics) to conform to the bowl-shaped slope without creating sharp "lippage" edges.
Should I subtract the area of a large window inside the shower?
Yes, if the window is large (more than 3 square feet). Measure the window's width and height, calculate its square footage, and subtract it from the raw total area before applying your waste factor. However, you must then measure the depth of the window sill and jambs, as you will need tile (and trim pieces) to wrap inside the window opening.
What happens if I do not order enough tile?
If you run short, you will have to pause your project and order more. The primary risk is that the new boxes will be manufactured in a different "dye lot." Tile colors vary slightly from batch to batch during manufacturing. A new box ordered weeks later may be visibly lighter or darker than the tile already installed on the wall.
How do I calculate thinset mortar and grout for a shower?
Thinset and grout coverage depends heavily on the size of your tile and the size of your trowel notches. Large tiles require deeper notches and consume much more thinset per square foot than small mosaic tiles. Check the back of the thinset or grout bag for the manufacturer's coverage chart, which will list exactly how many square feet a single bag covers based on trowel size.