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Grout coverage derived from the geometry a manufacturer's chart is made of

Laticrete publishes a grout coverage chart of 69 cells that looks like measured data. Run every cell backwards and they all give the same answer: 141.8 cubic inches per 8 lb bag. The entire chart is one constant divided by the joint geometry, and computing it forward lands on the published cells exactly, which means the same arithmetic works for your tile even though it is almost certainly not one of the 23 sizes on the chart.

Tile and grout quantities

ft
ft
in
in
in
in
%
no.

Grout coverage here is computed from the joint geometry, and it reproduces the published chart to within 3.3% on all 69 of its cells.

Specification summary

Generated from on . Reopen that address to reproduce these figures exactly.

Entered

Result

This figure is drawn from the tile you type in above.
The field at the real tile and joint proportions

Tile prices

Per sq ft, materials and labor together unless stated
ItemLowHighUnit
Ceramic$11$39per sq ft
Porcelain$13$48per sq ft
Travertine$9$32per sq ft
Limestone$18$65per sq ft
Granite$15$30per sq ft
Mosaic$13$57per sq ft
Glass$20$100per sq ft
Terracotta$7$14per sq ft
Labor only$3$15per sq ft

Source: This Old House, tile floor cost. Last price check: September 8, 2026.

Installed prices covering materials and labor together, so they are not comparable with a tile price off a shelf. Mosaic sits high for the reason this page gives: small tile is slow to lay and drinks grout.

Shower tiling prices

As each row states
ItemLowHighUnit
Tiling a shower$5$10per sq ft
Shower remodel$2,000$9,000total
Ceramic tile$0.50$100per sq ft, material
Porcelain tile$0.50$30per sq ft, material
Glass tile$10.50$25per sq ft, material
Acrylic shower unit$500$2,500total
Fiberglass shower unit$400$5,000total

Source: HomeAdvisor, how much does it cost to remodel a shower. Last price check: September 13, 2026.

The source prices ceramic tile at $0.50 to $100 per sq ft, a range too wide to budget from, and prices tiling at $5 to $10 per sq ft installed.

Drop ceiling and ceiling tile prices

As each row states
ItemLowHighUnit
Drop ceiling, typical project$1,073$3,333total
Standard, installed$9$13per sq ft
Full range, installed$5$28per sq ft
Labor$2$5per sq ft
Fiberboard tiles$1$7per sq ft
Black acoustic tiles$2$7per sq ft
Plastic tiles$5$9per sq ft
Metal tiles$12$20per sq ft
Wood tiles$10$70per sq ft
Light panel$20$50per fixture

Source: HomeAdvisor, how much does a drop ceiling cost. Last price check: September 15, 2026.

The source gives $9 to $13 per sq ft for standard installation and, a few lines later, $3.50 per sq ft on average for the same suspended ceiling.

Tile regrouting prices

As each row states
ItemLowHighUnit
Shower regrout, typical project$600$2,500total
Regrouting, installed$10$25per sq ft

Source: HomeAdvisor, how much does it cost to regrout a shower. Last price check: September 15, 2026.

The source states that its prices include complete removal of the old grout.

Vinyl and luxury vinyl flooring prices

As each row states
ItemLowHighUnit
Vinyl flooring, typical project$1,009$4,117total
Installation labor$3$10per sq ft
Vinyl sheet$1$2per sq ft
Luxury vinyl plank (LVP)$3$10per sq ft
Luxury vinyl tile (LVT)$2$10per sq ft
Standard vinyl plank$2$7per sq ft
Standard vinyl tile$1$4per sq ft
Subfloor repair$400$3,000total

Source: HomeAdvisor, how much does vinyl flooring cost. Last price check: September 15, 2026.

The source's size table works out to exactly $5 per sq ft at every size, a flat figure beside its own $3 to $10 installation rate.

Radiant floor heating prices

As each row states
ItemLowHighUnit
Radiant floor heating, typical project$1,653$6,656total
Installed$6$20per sq ft
In a concrete floor, average$22.50$22.50per sq ft
Under bathroom tile, average$30$30per sq ft
Installer$550$2,500total
Hydronic system, whole house$19,000$48,000total
Electric system, whole house$19,000$36,000total
Geothermal system$9,500$27,000total
Solar system$8,000$19,500total
Propane system$2,400$2,900total

Source: HomeAdvisor, how much does radiant floor heating cost. Last price check: September 15, 2026.

The source's $6 to $20 per sq ft sits below both of its own flooring examples, $22.50 in concrete and $30 under bathroom tile.

Worked example

A 12 ft by 10 ft floor in 12 by 12 in tile, 3/8 in thick, at a 1/8 in joint, with 10% waste.

  1. The cell. Each tile occupies 12.125 by 12.125 in with its joint, which is 1.02 sq ft.
  2. Tiles. 120 ÷ 1.02 = 118 tiles, or 130 with the allowance.
  3. Grout share. 1 − 144 / 147.02 = 2.1% of the floor is grout.
  4. Grout volume. 1.11 cu in per sq ft, so 133 cu in for the floor.
  5. Coverage. 141.8 ÷ 1.11 = 128 sq ft per 8 lb bag. Laticrete publishes 128 for this exact tile and joint. Two bags for the room.

That coverage figure is worth pausing on. The page did not look it up, it computed it from the joint geometry, and it landed on the published cell exactly. Do the same for 2 by 2 mosaic at the same joint and the geometry gives 34 sq ft a bag against Laticrete's published 34, also exact. Meanwhile the grout share has gone from 2.1% of the floor to 11.4% and a room that took two bags now takes eight. Nothing about the room changed. That relationship is why this page computes rather than looks up: your tile is probably not one of the 23 sizes on anybody's chart.

The formula

One rectangle does both quantities:

cell = (l + j)(w + j)    tiles = A / (cell/144)    grout = 144 (cell − lw) d / cell
l, w
tile length and width, in
j
grout joint, in. It belongs to the cell, not the tile
d
joint depth, which is the tile thickness if the joint is filled
A
floor area, sq ft
cell
the footprint one tile actually claims, joint included

The joint goes on one side of each tile, not both, because the next tile brings its own. Adding a full joint to each side double counts it and overstates the grout by about a factor of two, which is a common enough error that it explains most of the disagreement between the grout figures circulating online.

What happens when you check a chart instead of copying it

The published grout figures on the web disagree with each other badly. For a 12 by 12 tile at a 3/16 in joint, one page says a 25 lb bag covers 73 sq ft and another says 95 to 110. Those cannot both be right and neither cites anything.

Laticrete's data sheet is different: 69 cells, a document number, a stable address. So this page took it seriously and asked what generates it. The answer is that each cell is a bag volume divided by the exact geometry of the joint, and the bag volume is the same on every cell: 141.8 cubic inches, which is 8 lb of grout at about 97 lb per cubic foot.

That is worth more than the chart itself. A chart covers 23 tile sizes and your tile is probably not one of them, particularly now that large format and odd rectangles are normal. The formula covers everything, and it is checkable against the chart wherever the two overlap, which is what the table on this page shows.

Where they differ, the chart wins. Real tile is not exactly its nominal size, grout shrinks as it cures, and a bag is filled by weight rather than volume. The geometry is exact and its inputs are not.

The published chart, and the same chart predicted from geometry
Tile, inJointPublished, sq ft per 8 lb bagPredicted from geometryDifferenceGrout share of the floor
1 x 1 x 1/41/16"3434+1.5%11.4%
1 x 1 x 1/41/8"1919-1.2%21.0%
1 x 1 x 1/43/16"1414-3.3%29.1%
2 x 2 x 1/41/16"6666-0.0%6.0%
2 x 2 x 1/41/8"3434+1.5%11.4%
2 x 2 x 1/43/16"2424+0.0%16.4%
3 x 3 x 1/41/16"9797+0.5%4.0%
3 x 3 x 1/41/8"5050+0.5%7.8%
3 x 3 x 1/43/16"3434+1.5%11.4%
3 x 6 x 1/41/16"129129+0.1%3.1%
3 x 6 x 1/41/8"6666+0.1%6.0%
3 x 6 x 1/43/16"4545+0.2%8.7%
4 x 4 x 1/41/16"129129+0.0%3.1%
4 x 4 x 1/41/8"6666-0.0%6.0%
4 x 4 x 1/43/16"4545-0.0%8.8%
4.25 x 4.25 x 1/41/16"137137-0.1%2.9%
4.25 x 4.25 x 1/41/8"7070-0.1%5.6%
4.25 x 4.25 x 1/43/16"4848-0.8%8.3%
6 x 6 x 1/41/16"192192+0.0%2.1%
6 x 6 x 1/41/8"9797+0.5%4.0%
6 x 6 x 1/43/16"6666-0.0%6.0%
6 x 24 x 3/81/16"204204-0.1%1.3%
6 x 24 x 3/81/8"103103+0.0%2.5%
6 x 24 x 3/83/16"6969+0.6%3.8%
6 x 36 x 3/81/16"218218+0.2%1.2%
6 x 36 x 3/81/8"110110+0.3%2.4%
6 x 36 x 3/83/16"7474+0.4%3.5%
8 x 8 x 3/81/16"170170+0.0%1.5%
8 x 8 x 3/81/8"8686+0.0%3.1%
8 x 8 x 3/83/16"5858-0.0%4.5%
9 x 36 x 3/81/16"304305+0.2%0.9%
9 x 36 x 3/81/8"153153+0.3%1.7%
9 x 36 x 3/83/16"103103+0.0%2.5%
12 x 12 x 3/81/16"254254+0.0%1.0%
12 x 12 x 3/81/8"128128+0.0%2.1%
12 x 12 x 3/83/16"8686+0.0%3.1%
12 x 24 x 3/81/16"338338+0.0%0.8%
12 x 24 x 3/81/8"170170+0.1%1.5%
12 x 24 x 3/83/16"114114+0.1%2.3%
12 x 48 x 3/81/16"405406+0.1%0.6%
12 x 48 x 3/81/8"204204-0.1%1.3%
12 x 48 x 3/83/16"136137+0.5%1.9%
16 x 16 x 3/81/16"338338+0.0%0.8%
16 x 16 x 3/81/8"170170+0.0%1.5%
16 x 16 x 3/83/16"114114+0.0%2.3%
18 x 18 x 3/81/16"380380+0.0%0.7%
18 x 18 x 3/81/8"191191+0.0%1.4%
18 x 18 x 3/83/16"128128+0.0%2.1%
20 x 20 x 3/81/16"422422+0.0%0.6%
20 x 20 x 3/81/8"212212+0.0%1.2%
20 x 20 x 3/83/16"142142+0.0%1.8%
24 x 24 x 3/81/16"505506+0.2%0.5%
24 x 24 x 3/81/8"254254+0.0%1.0%
24 x 24 x 3/83/16"170170+0.0%1.5%
24 x 48 x 3/81/16"673674+0.2%0.4%
24 x 48 x 3/81/8"338338+0.0%0.8%
24 x 48 x 3/83/16"226226+0.1%1.2%
32 x 32 x 3/81/16"673674+0.2%0.4%
32 x 32 x 3/81/8"338338+0.0%0.8%
32 x 32 x 3/83/16"226226+0.0%1.2%
4 x 8 x 1/21/16"8586+0.7%2.3%
4 x 8 x 1/21/8"4344+1.3%4.5%
4 x 8 x 1/23/16"3030-1.5%6.7%
6 x 6 x 1/21/16"9696+0.0%2.1%
6 x 6 x 1/21/8"4949-0.5%4.0%
6 x 6 x 1/23/16"3333-0.0%6.0%
8 x 8 x 1/21/16"127128+0.4%1.5%
8 x 8 x 1/21/8"6465+0.8%3.1%
8 x 8 x 1/23/16"4343+1.2%4.5%

Read 2026-09-08. Column three is Laticrete's published figure. Column four is 141.8 cubic inches divided by the joint volume of that tile. Column six is how much of the finished floor is grout.

Download this table as CSV. Same cells as printed above, nothing added.

The coverage chart is one number and a rectangle

Laticrete publishes a grout coverage chart: 23 tile sizes across three joint widths, 69 cells, square feet per 8 lb bag. It reads like measured data.

It is arithmetic. Grout fills the space between tiles, so a tile of L by W laid at a joint of j occupies a cell of (L+j)(W+j), and the grout in that cell is what is left over, times the joint depth:

cu in per sq ft = 144 × ((L+j)(W+j) − LW) × d / ((L+j)(W+j))

Run all 69 published cells backwards through that and ask what bag volume each implies. They agree: 141.8 cubic inches per 8 lb bag, every time. Predict the whole chart forward from that single constant and the worst cell is 3.3% out.

And the constant is just a density. 8 lb in 141.8 cubic inches is about 97 lb per cubic foot, which is what mixed grout weighs. There is nothing else in the table.

Which is worth knowing for the case the chart does not list. Your tile is probably not one of those 23 sizes, and the calculator above does the same arithmetic for whatever you actually have.

The joint belongs to the cell, not the tile

This is where most tile arithmetic goes wrong, and it goes wrong by a factor of two.

A tile laid in a field has a joint on each of its four sides, but each joint is shared with the neighbor. So the footprint one tile claims is the tile plus one joint in each direction: (l + j) by (w + j), not (l + 2j) by (w + 2j).

Add a full joint on both sides and you overstate the grout by roughly double and understate the tile count slightly. It is the likeliest explanation for why the coverage figures floating around for the same tile and joint differ by 50% and more.

The perimeter of the room is the exception, where there is a joint against the wall with no neighbor, but that is a rounding error next to the field and it is inside the waste allowance.

Waste, and the layouts the allowance does not cover

The 10% default is ours and it is for a plain, square room laid straight, where offcuts from one end of a run start the next.

It does not cover a diagonal layout, where every tile at every wall is cut at 45 degrees and the offcut is a triangle that fits nowhere. Fifteen percent is the usual working figure and it is still not generous.

It does not cover a pattern with a repeat, herringbone or basketweave, where the cut pieces have to be specific sizes rather than whatever is left.

And it does not cover a room that is not square, which is most rooms. A wall out by an inch over 12 ft means the cut tiles along it are all different, and none of the offcuts are interchangeable.

Buy the whole job at once and check the lot number. Tile shade varies between production runs, and a second delivery to make up a shortfall rarely matches the first. That is the real cost of under-ordering, not the extra trip.

What this page does not do

Thinset. Coverage depends on the trowel notch, the tile size and how flat the substrate is, and manufacturers publish it per trowel rather than per tile. It is a different chart and a different question.

Substrate flatness. Large format tile is unforgiving of a floor that is out, and the flatness tolerances live in ANSI A108, which is not a free document. Lippage is the commonest complaint on a large format floor and it is a substrate problem, not a tile problem.

Movement joints. Where they go and how wide is a design question, and on a large floor it is not optional.

Why a mosaic drinks grout and a large format does not

The share of a finished floor that is grout depends on the tile size far more than on the joint:

grout share = 1 − LW / ((L+j)(W+j))

A 1 x 1 mosaic at a 1/8 in joint is 21% grout by area. A 12 x 12 at the same joint is 2.1%. Same joint width, same room, and roughly 10 times the grout.

That is why a mosaic floor empties bags at a rate that shocks anyone whose experience is 12 inch tile, and why a shower floor of penny round can need more grout than the walls around it need despite being a fraction of the area.

It also cuts the other way on large format. A 24 x 48 at 1/16 in is under 0.4% grout, so a single bag goes a long way and the joint stops being a material question at all.

Joint depth matters as much as width and is the quieter variable. The chart assumes grout to the full tile thickness. If the joint is not filled to the bottom, coverage goes further and the joint is weaker, and if the tile is thicker than the chart's assumption you will use more than it says.

The chart this page was checked against

Read 2026-09-08. LATICRETE PERMACOLOR Grout, product data sheet, Laticrete DS-250-0926. 23 tile sizes across three joint widths, 69 cells. Every one of them is reproduced here by dividing 141.8 cubic inches by the joint geometry, worst case 3.3% out.

The published chart wins where they differ. The geometry here is exact but the inputs to it are not: real tile is not exactly its nominal size, grout shrinks slightly as it cures, and a bag is filled by weight rather than volume. Where your tile is on the chart, use the chart. Where it is not, which is most of the time, the arithmetic above is what the chart itself is made of.

Why one manufacturer. Laticrete publishes a full coverage chart at a stable public address with a document number on it. The figures circulating elsewhere for the same tile and joint disagree with each other by more than 50%, which is what happens when a number is copied rather than sourced.

Frequently asked questions

How many 12x12 tiles do I need for a 120 square foot room?
About 118 before waste. Each tile with a 1/8 in joint occupies 12.125 by 12.125 in, which is 1.02 sq ft, so 120 divided by 1.02 is 118. With a 10% allowance for cuts you would buy 130.
How much grout do I need per square foot?
It depends on the tile size far more than on the joint. A 12 by 12 tile at a 1/8 in joint needs 0.74 cubic inches per square foot. A 2 by 2 mosaic at the same joint needs about 4 cubic inches per square foot, five times as much, because the grout share of the floor goes from 2.1% to 11.4%.
How many square feet does a bag of grout cover?
For an 8 lb bag, 192 sq ft on 12 by 12 tile at a 1/8 in joint, but only about 35 sq ft on 2 by 2 mosaic at the same joint. There is no single answer, which is why manufacturers publish a chart rather than a number. The chart is 141.8 cubic inches divided by the joint volume of that particular tile.
Why do grout coverage figures online disagree so much?
Mostly because the joint gets counted twice. Each tile shares its joints with its neighbors, so a tile claims a cell of (length + joint) by (width + joint), not plus two joints. Counting a full joint on every side roughly doubles the grout figure. Different assumptions about joint depth account for most of the rest.
Does a bigger grout joint use much more grout?
Less than people expect, and far less than changing the tile size. On 12 by 12 tile, going from a 1/16 in joint to 3/16 in triples the grout, but it is tripling a figure that was only 1% of the floor to start with. On a 1 by 1 mosaic the same change takes you from 11% of the floor to 29%.
How much extra tile should I buy?
Ten percent for a plain straight layout in a square room. Fifteen for a diagonal, because every perimeter cut is a triangle that fits nowhere else, and more again for herringbone or any pattern with a repeat. Buy it all in one order and check the lot number: shade varies between production runs.
What thickness should I use for the grout depth?
The tile thickness, if the joint is filled properly. That is what the published charts assume. A joint that is not filled to the bottom will make the grout go further and will be weaker, and it is where cracking starts.
How do I find the square footage for a tile job?
Multiply length by width in feet for each rectangle and add them together: the worked example is 12 ft by 10 ft, which is 120 square feet. The calculator divides that footage by the area one tile claims with its joint, not by the bare tile. For a kitchen backsplash, enter the run of the counter as the length and the tiled height as the width, because the joint geometry on a wall is the same as on a floor.
What does tile installation labor cost per square foot?
This Old House puts labor only at $3 to $15 per square foot, against $11 to $39 for a ceramic floor with materials included. On the 120 square foot worked example that is $360 to $1,800 of labor. Laying the tile is what that row prices, so the tile itself goes on top of it. The source's mosaic row runs high, which fits the arithmetic on this page: small tile means more pieces and more joint in every square foot.
How much does it cost to tile a bathroom?
The two sources on this page price it in parts. This Old House gives $11 to $39 per square foot for a ceramic floor, materials and labor together, and HomeAdvisor gives $5 to $10 per square foot for tiling a shower, inside a shower remodel of $2,000 to $9,000. Measure the bathroom floor and the tiled shower walls separately, because they sit on different rows.
Are clay tiles the same as ceramic or terracotta?
Ceramic, porcelain and terracotta tile are all made from fired clay. This Old House prices terracotta at $7 to $14 per square foot installed, ceramic at $11 to $39 and porcelain at $13 to $48. The tile and grout counts here do not depend on the material at all, only on the tile size, the joint and the thickness.
How much does a heated tile floor cost?
HomeAdvisor's radiant floor heating guide gives $6 to $20 per square foot installed, and an average of $30 per square foot under bathroom tile. On the 120 square foot worked example that is $720 to $2,400 at the installed rate, or about $3,600 at the bathroom tile average. The tile itself is a separate line: ceramic at $11 to $39 per square foot installed is another $1,320 to $4,680.
What does a tiled tub surround or subway tile backsplash cost?
Neither source prices a tub surround or a backsplash as its own job. The only wall tile rate on this page is HomeAdvisor's $5 to $10 per square foot for tiling a shower. Subway tile is a rectangular wall tile, and the calculator counts it from its length and width like any other tile.
How much does a shower remodel cost?
HomeAdvisor's June 2026 guide gives $2,000 to $9,000 for a shower remodel, $7,000 on average. Tiling the shower is $5 to $10 per square foot of wall, with ceramic tile itself from $0.50 to $100 per square foot and porcelain $0.50 to $30. A one-piece acrylic unit is $500 to $2,500 and fiberglass $400 to $5,000. Measure the shower walls on this page to price the tile.
How much does it cost to lay floor tile?
This Old House's June 2026 article gives installed prices per square foot of floor: ceramic $11 to $39, porcelain $13 to $48 and travertine $9 to $32, with labor alone at $3 to $15. Multiply by the floor area this page measures, not by the number of tiles.
How much do ceiling tiles for a suspended ceiling cost?
HomeAdvisor's June 2026 guide gives $9 to $13 per square foot for a standard drop ceiling installed. The tiles alone run $1 to $7 for fiberboard, $5 to $9 for plastic and $12 to $20 for metal, with labor at $2 to $5.
How much does it cost to regrout tile?
HomeAdvisor's June 2026 guide gives $10 to $25 per square foot, and $600 to $2,500 for a typical shower.
How much does luxury vinyl plank flooring cost?
HomeAdvisor's June 2026 guide gives $3 to $10 per square foot for luxury vinyl plank, $2 to $10 for luxury vinyl tile and $1 to $2 for sheet vinyl, with installation labor at $3 to $10. Sheet vinyl is the modern equivalent of linoleum, though the guide prices them together.
How much does it cost to remove a tile floor?
This Old House's June 2026 article gives $1 to $6 per square foot to remove an existing floor, tile included. A 100 sq ft bathroom floor is $100 to $600 to tear up at that rate.
Is tile cheaper than wood flooring?
They overlap. This Old House's June 2026 article gives $11 to $39 per square foot for ceramic tile installed and $13 to $48 for porcelain. This Old House's June 2026 article gives $6 to $18 per square foot for hardwood installed, so hardwood is cheaper at the low end and ceramic tile costs more at the top.
How much does it cost to tile a walk in shower?
HomeAdvisor's June 2026 guide gives $5 to $10 per square foot to tile a shower and $2,000 to $9,000 for a whole shower remodel. A walk-in shower with 100 sq ft of wall is $500 to $1,000 to tile at that rate, before the tile itself.

Check these numbers yourself

How every figure here is verified: Sources & Method. Who builds this: , and the method is on About. Found something wrong? Tell us and it gets fixed or removed.

Figures on this page last checked against the source documents on 2026-09-08. Codes are amended locally; confirm against the edition your jurisdiction enforces.

Related calculators

Guides that use this calculator

More of them: all guides.

Where the published chart covers your tile, use the chart. The geometry here is exact but its inputs are not: real tile is not exactly its nominal size, grout shrinks as it cures, and a bag is filled by weight rather than volume. Laticrete's chart was read on 8 September 2026. Thinset coverage, substrate flatness tolerances and movement joints are not covered on this page.