Shower Tile Calculator: How Much Tile for a 60×32 Alcove

A shower wall order is three rectangles, a waste allowance, and whole boxes. This page works a 60 in by 32 in alcove, the narrower tub-surround opening, tiled 8 ft (96 in) high. Measure the back wall and each return on its own, add those areas, and only then add waste. Once the square footage is written down, the tile calculator is the shower tile calculator for the last step: installation area, waste allowance, and coverage per box. It does not decide which walls, niches, or curbs belong in the job.

The same wall-by-wall habit is the general method in how much extra tile to buy. A backsplash uses shorter rectangles and a lower allowance. The kitchen backsplash guide adds each section before a 10 percent waste. Shower corners and valve cuts are why this worksheet uses 15 percent for a straight lay instead.

Shower square footage, one wall at a time

Do not wrap one tape around the three walls and call that a perimeter. Studs are often out of square, and a corner is where a tile is cut, not where two walls share an area. Measure each plane from the inside corner to the outer edge of the surface you will actually tile.

Record width and tiled height in inches, then convert once. A 32 in return is 32 ÷ 12 = 2.667 ft, not 0.32 ft and not 3 ft. Height starts at the top of the curb or the tub flange and stops at the tile line you intend to install. An 8 ft ceiling line is 96 in. If the tile stops on a chair rail or at 7 ft, use that height. Do not borrow the 96 in figure from this example after the design has changed.

Multiply each wall in square inches, add the inches, and divide by 144. NIST Handbook 133 Appendix E states that 1 square foot is 144 square inches. That single conversion is the square-footage step: three wall areas in, one square-foot total out. Keep the inch totals on the sheet so a feet-and-inches mix can be checked before the waste percent hides the mistake.

Do not subtract the mixing valve, the showerhead, or a small niche opening. Those cuts still come out of full tiles, and the offcut is rarely reusable on the opposite corner. Keep the wall rectangle. If the niche interior is tiled, add its back, jambs, sill, and head as their own line. A large window that is truly left untiled is a named deduction, and any tiled jambs are added back. The backsplash waste guide uses the same rule for outlets: a small cut changes the layout without saving a carton.

The floor, the curb top, and the curb face are not part of the three walls. Add them only when they use the same field tile, and keep each one on its own line. Bullnose, pencil liner, jolly strip, and corner trim are linear pieces in their own packages. Field-tile square footage does not include them, and leftover field tile does not satisfy a missing trim length.

Calculating tile overage

Tile overage is the waste percent applied after the square footage is finished. Calculating tile overage means multiplying that measured area by 1 + waste, then dividing by the coverage printed on the box. The percent does not repair a forgotten return or a height recorded in the wrong unit.

Lowe’s tile estimating guidance uses 10 percent extra for trim and waste as a general planning reference. The Home Depot backsplash guide also adds 10 percent after the section areas are summed. This shower worksheet does not copy that 10 percent onto walls. A straight or brick-lay shower has two internal corners on every course, plus a round cut at the valve, and the piece cut off one corner rarely starts the next row. The documented allowance here is 15 percent, so the multiplier is 1.15.

Use 20 to 25 percent when the layout is diagonal, herringbone, or large-format. Those cuts throw away more of each piece, and a large tile that crosses a corner often loses a slice too narrow to reuse. The herringbone floor guide applies that same 20–25 percent range when the pattern moves onto a wall. A flat 5 percent allowance usually runs short on the top courses or the niche returns.

The box-conversion guide keeps square feet, piece count, and cartons as separate results. Read coverage from the carton you will buy. Two products with the same nominal size can cover different amounts per box, and a labeled coverage figure already reflects the joint the manufacturer used. Do not invent a second joint allowance on top of the label, and do not multiply nominal tile dimensions and call the product a box yield.

The tile calculator waste field defaults to 10 percent, which matches the general Lowe’s reference and does not match this shower. Change it to 15 for a straight lay before you read the box count. Round up to a whole box. Square feet left over because the last carton was purchased whole are already in the order. Do not add the waste percent a second time to “cover” that rounding.

Worked example

The alcove is 60 in across the back and 32 in on each return. Tile runs 96 in high, from the tub flange or curb to the ceiling line. The layout is a straight or brick lay. The selected carton covers 12.5 square feet. The allowance is 15 percent.

Wall	Measurement	Square inches
Back	60 in × 96 in	5,760
Left return	32 in × 96 in	3,072
Right return	32 in × 96 in	3,072
Field total		11,904

Convert the field total with the NIST factor:

11,904 ÷ 144 = 82.667 square feet

That quotient is exactly 82 2/3 square feet. The figure 82.667 is 82 2/3 rounded to three decimal places. Each return alone is 3,072 ÷ 144 = 21.333 square feet at three decimals, and the back wall is exactly 40 square feet. Add the square inches when you check the total. Adding the rounded line items is 0.001 square foot low and is not the worksheet total.

Apply the 15 percent overage to the exact area, then round the display:

11,904 ÷ 144 × 1.15 = 95.067 square feet

Divide by the carton coverage:

95.067 ÷ 12.5 = 7.605 boxes

Cartons are sold whole. The three shower walls require 8 boxes after the documented 15 percent allowance. Eight boxes are 8 × 12.5 = 100 square feet. The surplus over the 95.067 square foot target is 4.933 square feet. That surplus is whole-box rounding, not another 15 percent.

Enter 82.667 as the installation area, 15 as the waste allowance, and 12.5 as the coverage per box in the tile calculator. The result is the same 8-box order. At this particular 12.5 square foot carton, leaving the waste field at the 10 percent default still rounds to 8 boxes, because 11,904 ÷ 144 × 1.10 = 90.933 square feet and 90.933 ÷ 12.5 = 7.275 boxes. The 15 percent plan still asks for more installed coverage inside those eight boxes: 95.067 square feet versus 90.933. The box count splits as soon as the carton is smaller. At 11.5 square feet per box, 15 percent is 95.067 ÷ 11.5 = 8.267, which is 9 boxes, and 10 percent is 90.933 ÷ 11.5 = 7.907, which is 8 boxes. Keep 15 percent when that is the allowance you chose. Do not keep 10 percent only because one carton size hid the difference.

A recessed niche is extra area, not a deduction. For a 12 in by 24 in niche that is 4 in deep, tile the back, both jambs, the sill, and the head, and leave the wall rectangle intact:

12 × 24 = 288 square inches for the back

2 × 24 × 4 = 192 square inches for the jambs

12 × 4 = 48 square inches for the sill, and the same 48 for the head

288 + 192 + 48 + 48 = 576 square inches, or exactly 4 square feet

(11,904 + 576) ÷ 144 = 86.667 square feet

86.667 × 1.15 = 99.667 square feet

99.667 ÷ 12.5 = 7.973 boxes

That still rounds to 8 boxes at 12.5 square feet per box. The niche consumes most of the 4.933 square foot rounding surplus, so it belongs on the sheet even when it does not add a ninth carton. A deeper niche, or the 11.5 square foot carton above, can push the order over the next whole box.

The shower floor is a separate rectangle. The opening is 60 × 32 = 1,920 square inches, or 1,920 ÷ 144 = 13.333 square feet. If the floor uses the same field tile, add it before the waste percent: (11,904 + 1,920) ÷ 144 = 96 square feet, then 96 × 1.15 = 110.4 square feet, then 110.4 ÷ 12.5 = 8.832 boxes, which is 9 boxes. The 8-box result on this page is walls only.

A curb finished in field tile is also its own line. A 60 in curb with a 4 in top and a 6 in outside face is 60 × 4 + 60 × 6 = 600 square inches, or 4.167 square feet. Add that area before the 15 percent. It is not inside the 8-box wall total.

A wider 5 ft by 3 ft alcove is the 60 in by 36 in opening. At the same 96 in height the back is still 5,760 square inches, and each return is 36 × 96 = 3,456 square inches. The three walls are 5,760 + 3,456 + 3,456 = 12,672 square inches, or exactly 88 square feet. The straight-lay allowance is the same 15 percent: 88 × 1.15 = 101.2 square feet. At 12.5 square feet per box, 101.2 ÷ 12.5 = 8.096, so that wider alcove is 9 boxes. The 5×3 example adds each wall before the 15 percent waste, and it uses 15 percent for a straight lay. The 60×32 opening is the same method with a shorter return.

Measurement checklist

1. Draw the back wall, the left return, and the right return as separate rectangles.
2. Measure each width at the surface that will receive tile, not as one wrapped perimeter.
3. Measure height from the curb or tub flange to the actual tile stop, and write that height in inches.
4. Convert inches with ÷ 12 for a side in feet, or stay in square inches and divide by 144 once.
5. Add niche back, jambs, sill, and head without deducting the niche opening from the wall.
6. Mark the valve and showerhead as cuts. Do not subtract their face area.
7. Add the floor, curb top, and curb face only when those surfaces use the same field tile.
8. Count bullnose, jolly, and corner pieces in linear feet or pieces, on a separate purchase line.
9. Choose 15 percent for a straight or brick lay, and 20 to 25 percent for diagonal, herringbone, or large-format tile.
10. Read square-foot coverage from the carton. Do not infer it from the nominal tile name.
11. Set the tile calculator waste field to the percent you documented. Do not leave the 10 percent default in place by habit.
12. Divide the allowance-adjusted area by box coverage and round up to whole boxes.
13. Record shade, caliber, and lot before you leave the store. A later box from another lot is a poor repair stock.

Common failure modes

• Wrapping one tape around the alcove. A perimeter length still needs a separate height for each wall, and one wrapped number hides an out-of-square corner.
• Reading 32 inches as 0.32 foot or as a full 3 feet. The return is 32 ÷ 12 feet. That error alone moves the field by several square feet on each side.
• Deducting the valve, the head, or the niche opening. The cut consumes a full tile. The niche interior, if tiled, is added.
• Stopping at the three walls when the floor is the same tile. The 60×32 floor is 13.333 square feet and, with the walls at 15 percent, changes this example from 8 boxes to 9.
• Using 5 or 10 percent because a floor guide said so. Those figures are planning references for simpler layouts. This straight-lay shower documents 15 percent, and a herringbone wall documents 20 to 25 percent.
• Trusting the calculator default. The waste field opens at 10 percent. At 12.5 square feet per box the 60×32 walls still round to 8 either way; at 11.5 square feet per box, 10 percent is 8 boxes and 15 percent is 9.
• Pooling trim into the field cartons. Bullnose and corner pieces have their own counts. A surplus of field tile does not cut into a finished edge.
• Rounding the box count down, or adding waste twice. A 7.605 result is 8 boxes. The 4.933 square feet inside that eighth box are the rounding surplus, not a reason to multiply by 1.15 again.
• Replacing the carton label with nominal tile math. Purchasing follows the coverage printed on the box you selected.

Limitations and verification

This guide estimates field-tile quantity for a dimensioned shower. It does not size backer board, a waterproofing membrane, thinset, grout, or a linear drain. It does not decide whether a wall is ready for tile, which mortar matches the tile and the substrate, or how a niche should be waterproofed. Follow the current product instructions, and use a qualified installer where the wet-area detail is outside the quantity worksheet.

The Home Depot source supports section-by-section measurement, attention to outlets and switches in the layout, and its stated 10 percent addition on a backsplash. The Lowe’s source supports 10 percent as general tile-estimating guidance. Neither source sets 15 percent as a shower rule, and neither replaces the carton label. The 15 percent figure on this page is the documented allowance for a straight or brick-lay shower with corner cuts and a valve. The NIST source supports the 144 square inches in one square foot used to convert the example.

Before you order, compare the three wall drawings, the inch total, the square-foot total, the waste percent, the carton coverage, the exact division, and the rounded box count. Recalculate when the tile line, the niche, the floor, the pattern, or the product changes. If a measurement boundary or an arithmetic result on this page looks wrong, report it through the corrections page so the guide and the calculator can be checked together.