How Many Tiles for a Shower Wall

A straight layout changes the tile count more than the room size does, because the pattern decides how many tiles get cut — and every cut is tile you bought but did not lay. The honest answer is a range, and this article builds that range step by step, with every number shown so you can check it against the label on the box you buy.

A straight grid layout lines every tile up in rows and columns. It has the fewest cuts of any layout, so its waste range is the lowest. Every figure below is a range, and the label on the box you buy governs. Results on this page are estimates: coverage, pack sizes, yields and prices vary by brand, product line, surface and region, and the label on the product you buy governs. That warning matters more than it sounds — two products that look identical on a shelf can pack differently, cover differently and cost differently, and the only figure that counts at the checkout is the one printed on the exact product in your cart. Keep the range in mind as you read: where this article gives a low end and a high end, plan your order on the high end and keep the receipt for anything unopened.

How the calculation works

The calculator needs four inputs, and each one changes the answer. First, the area: length times width, minus anything that will not be tiled — for an 8 ft by 10 ft shower wall area that is 80 sq ft (7.4 sq m) before deductions. Second, the tile size: 3x6 in (7.6x15 cm) subway tile is typically used for backsplashes and shower walls, and one box typically holds about 40 pieces covering about 5 sq ft — a typical figure from our material data, so the carton label governs. Third, the waste allowance, which is where the pattern lives: a straight or grid layout typically needs 5–10% extra, a brick or offset layout 10–15%, and a diagonal or herringbone layout 15–20%. A straight layout uses the 5–10% range. Fourth, the extras: grout typically covers about 10–25 sq ft per lb, and thinset adhesive typically covers about 40–60 sq ft per 50 lb (22.7 kg) bag.

The formula is short: boxes = (net area × (1 + waste %)) ÷ coverage per box, rounded up. Always round up — a box cannot be bought in fractions, and a half-box shortfall at the end of a job is the most expensive kind of shortfall. Note what the formula leaves out on purpose: it does not assume a single coverage rate. If a retailer quotes one number for coverage, treat it as a starting point and check the carton — the range is the honest figure.

Worked example

Here is the full arithmetic for an 8 ft by 10 ft shower wall area, covering 80 sq ft (7.4 sq m) with 3x6 in (7.6x15 cm) subway tile.

Step 1 — net area. The area to tile is 80 sq ft. Measure each run separately and deduct anything that will not be tiled before you start.

Step 2 — add waste. The layout here uses a 5–10% waste allowance. At 5% waste: 80 × 1.05 = 84 sq ft. At 10% waste: 80 × 1.10 = 88 sq ft. So you need to buy for 84–88 sq ft of tile.

Step 3 — convert to boxes. One box of 3x6 in (7.6x15 cm) subway tile typically holds about 40 pieces and covers about 5 sq ft per box — a typical figure from our material data, so check the carton label. 84 ÷ 5 = 16.8 boxes; 88 ÷ 5 = 17.6 boxes. Rounded up, that is 17–18 boxes — buy the high end and keep one unopened box for future repairs.

Step 4 — grout and adhesive. Grout at the typical 10–25 sq ft per lb means about 3.2–8 lb for 80 sq ft. Thinset at 40–60 sq ft per 50 lb bag means 2 bags. Buy the high end of both if your joints are wide or your trowel notch is large.

Scale the same steps for any other area: measure, deduct, apply the waste range for your layout, divide by the per-box coverage on your carton label, and round up. The waste percentage stays tied to the layout, not the room size.

What changes the answer

Three mistakes account for most of the wasted money on a straight layout. The first is measuring once and trusting it — a single wrong wall length multiplies through the whole order. The second is ordering the low end of a range and discovering the shortfall on the last row. The third is ignoring the label: pack sizes and coverage change between product lines, and the calculator's typical figures are a planning aid, not a promise.

Underestimating the pattern. A straight layout on an 8 ft by 10 ft shower wall area needs 5–10% extra, not the 5–10% a straight grid needs. Ordering straight-grid waste for a patterned layout is the most common way to run short.

Starting in the wrong place. Patterned layouts look wrong if the first row is laid against the most visible wall without centring. Dry-lay the pattern first, centre it on the room, and only then mix adhesive — moving a set tile is far harder than moving a dry one.

Forgetting the grout. A straight layout in 3x6 in (7.6x15 cm) subway tile still needs grout: about 3.2–8 lb for 80 sq ft at the typical 10–25 sq ft per lb. Order it with the tile, from the same batch.

Cost guidance

Costs on this page are ranges, labelled typical retail range — check the current shelf price before budgeting. No single national price is quoted, because tile prices vary by brand, product line, region and retailer, and a price that is right in one store can be wrong in the next. The way to budget is to multiply, not to guess: take the box count from the worked example (17–18 boxes of 3x6 in (7.6x15 cm) subway tile), multiply it by the shelf price per box on the exact product you have chosen, then add 8 lb of grout at the top of the range and the thinset bags, each priced from the shelf where you buy them. Then add the consumables and the extras — spacers, tools you do not own, sealer where the material needs it — and compare the total, not the per-box price.

Two cost traps catch first-time buyers. The first is ordering the low end of the range and then paying a second delivery charge — or a higher per-box price — for the one box that finishes the job. The second is forgetting the consumables: on a small job they are a meaningful share of the material cost. Keep one unopened box for future repairs; a matching dye lot is worth far more than the shelf price of that box later. If you are hiring the work out, labour is usually quoted separately and varies by region and by the complexity of the job, so get the quote against the same measurements you used for the material count.

Step by step: measure, calculate, order

1. Measure twice. Measure every run in feet at the longest and widest points, and measure each alcove, niche and angle separately. Rooms are rarely perfect rectangles — sketch the shape on paper, convert inches to decimal feet (6 in = 0.5 ft) before multiplying, and note anything you will deduct.

2. Choose the material and the layout. Pick the 3x6 in (7.6x15 cm) subway tile first, then commit to the straight layout — the pattern decision belongs before the order, because it sets the waste range (5–10% here) and the labour.

3. Use the calculator on this page. Enter the net area, the tile size (3x6 in (7.6x15 cm) subway), and the waste percentage for a straight layout. The tool returns a range — 17–18 boxes for the example above — and you should plan on the high end. Check the carton label against the calculator's assumed 5 sq ft per box.

4. Order and check the delivery. Order 18 boxes for the example job, all from the same dye lot, and check the lot numbers on the cartons before the tiler starts. Keep the grout and adhesive dry and within their shelf life.

5. Before you start. Dry-lay the pattern across the room to check the cuts at the edges and the centring, confirm the substrate is flat and clean, and make sure you have spacers, a level, a suitable trowel and a spare box within reach.

Frequently asked questions

How many tiles do I need for a straight layout on 80 sq ft?

About 17–18 boxes of 3x6 in (7.6x15 cm) subway tile, using the 5–10% waste range for a straight layout. A straight grid layout lines every tile up in rows and columns. It has the fewest cuts of any layout, so its waste range is the lowest. Order the high end and keep an unopened box for repairs.

How much waste should I add for a straight pattern?

Typical waste ranges are 5–10% for a straight or grid layout, 10–15% for brick or offset, and 15–20% for diagonal or herringbone. A straight layout uses 5–10% here. Small rooms, angled walls and lots of fixtures all push you toward the high end of your layout's range.

How many 3x6 in (7.6x15 cm) subway tiles are in a box?

Typically about 40 pieces per box, covering about 5 sq ft — but that is a typical value from our material data, not a promise. The carton label on the exact product you buy governs. Always confirm the pieces per box and the sq ft per box on the label before you order.

How much grout do I need for 80 sq ft in a straight layout?

Grout typically covers about 10–25 sq ft per lb depending on joint width, so 80 sq ft needs about 3.2–8 lb. The pattern itself does not change the grout much — joint width and tile size do — so buy the high end if your joints are wide.

Is a straight layout harder to install than a straight grid?

Yes — patterned layouts need more cuts, more setting out and more time, and the labour is usually quoted higher for them. The material count is simple, at about 5 sq ft per box, but the setting out is not. Dry-lay the pattern before you mix any adhesive.

Related calculators

Results are estimates — verify with the product label. Coverage, pack sizes, yields and prices vary by brand, product line, surface and region; the label on the product you buy governs. Cost figures are typical retail ranges — check the current shelf price before budgeting.