Grout Coverage Chart

Every bag of grout has a coverage figure on it, and it is always given as a range because coverage is not a property of the grout — it is a property of your tile. Two tiles of the same size with different joint widths can differ by a factor of four. This works out the real number for your job.

Tile width (in)

Tile length (in)

Tile thickness (in)

Joint depth equals tile thickness on a full joint

Joint width

Bag size

One 25 lb bag covers

471 sq ft

Grout type for this joint: Sanded
Pounds per sq ft: 0.053 lb
Joint volume per sq ft: 0.83 cu in
Allowing 10% waste: 428 sq ft per bag

Coverage assumes joints packed full to the tile thickness. A joint left shallow uses less grout and fails sooner.

Square feet per 25 lb bag, by tile and joint

Coverage of one 25 lb bag, assuming 3/8 in thick tile and full joints

Tile size	1/16" joint	1/8" joint	3/16" joint	1/4" joint
1 x 1 in mosaic	70 sq ft	35 sq ft	25 sq ft	20 sq ft
2 x 2 in mosaic	134 sq ft	64 sq ft	44 sq ft	35 sq ft
3 x 6 in subway	262 sq ft	122 sq ft	83 sq ft	64 sq ft
4 x 4 in	262 sq ft	122 sq ft	83 sq ft	64 sq ft
4 x 12 in	391 sq ft	180 sq ft	122 sq ft	93 sq ft
6 x 6 in	390 sq ft	180 sq ft	122 sq ft	93 sq ft
6 x 24 in plank	621 sq ft	285 sq ft	192 sq ft	146 sq ft
12 x 12 in	774 sq ft	355 sq ft	238 sq ft	180 sq ft
12 x 24 in	1030 sq ft	471 sq ft	316 sq ft	238 sq ft
18 x 18 in	1158 sq ft	529 sq ft	355 sq ft	267 sq ft
24 x 24 in	1542 sq ft	704 sq ft	471 sq ft	355 sq ft
24 x 48 in	2054 sq ft	937 sq ft	626 sq ft	471 sq ft

Read across: the same bag covers vastly different areas depending on the tile. Mosaic at a wide joint is the extreme case and the one most often under-ordered.

Pounds per 100 sq ft

The same geometry expressed as pounds needed per 100 sq ft

Tile size	1/16" joint	1/8" joint	3/16" joint	1/4" joint
1 x 1 in mosaic	36 lb	72 lb	100 lb	124 lb
2 x 2 in mosaic	19 lb	39 lb	56 lb	72 lb
3 x 6 in subway	10 lb	21 lb	30 lb	39 lb
4 x 4 in	10 lb	21 lb	30 lb	39 lb
4 x 12 in	6 lb	14 lb	20 lb	27 lb
6 x 6 in	6 lb	14 lb	21 lb	27 lb
6 x 24 in plank	4 lb	9 lb	13 lb	17 lb
12 x 12 in	3 lb	7 lb	11 lb	14 lb
12 x 24 in	2 lb	5 lb	8 lb	11 lb
18 x 18 in	2 lb	5 lb	7 lb	9 lb
24 x 24 in	2 lb	4 lb	5 lb	7 lb
24 x 48 in	1 lb	3 lb	4 lb	5 lb

Add about 10% on top of these figures for waste. Both tables come from the same function the calculator uses, so they cannot drift apart from it.

What changes the number most

Tile size, by a wide margin. Joint length per square foot is roughly proportional to the tile's perimeter divided by its area, so halving the tile roughly doubles the grout. A mosaic floor and a large-format floor of the same square footage are not in the same ballpark.

Joint width, proportionally. Going from 1/16 inch to 1/4 inch is four times the width and close to four times the grout.

Joint depth, proportionally. Normally the tile thickness. This is the one people leave out, and it is why the same tile face size in thick porcelain and thin ceramic need different amounts.

Once you have the coverage, size the rest of the job: the grout calculator converts it to bags for your area, thinset covers what goes under the tile, and tile spacers sets the joint width you have just been calculating for.

Do this math on the job site — in the free app

Smart Tile Calculator for Android: offline, in your pocket, no ads. iPhone version coming soon.

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Tools the pros use for this job

Grout Float
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A stiff float packs the joint full instead of skimming the top, which is what the coverage figure assumes.
Grout Sponge
BARWALT Ultra Tile Grouting System, Grout Bucket Kit, Assembled in the USA | Grate and Slotted Sponge Sift Grout, Cuts Grouting Time Nearly in Half, Includes Wall and Floor Sponge, BWT81584
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Rounded edges clean haze without dragging grout back out of the joint.
Mixing Bucket
Mixing Bucket
Mixing part-bags is where colour variation between batches comes from.
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Mixing part-bags is where colour variation between batches comes from.

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How this calculator works

Grout fills the space between tiles, so the volume you need is the volume of that space. Laid in a grid, each tile sits in a repeating cell measuring (tile width + joint) by (tile length + joint). Subtract the tile's own footprint from that cell and you have the joint area belonging to one tile; multiply by the joint depth and you have its volume.

Volume per sq ft = [(W + J)(L + J) − W×L] × D ÷ [(W + J)(L + J) ÷ 144]

That part is exact — no product data involved. Turning volume into pounds needs one more number, the density of the mixed grout, and that genuinely does vary by product: around 100 lb per cubic foot for unsanded, 110 for sanded and 125 for epoxy. If your bag prints a coverage figure, it is doing this same calculation with its own density; if the number here differs from the bag, trust the bag and treat this as the sanity check.

The mistake that makes published charts disagree with each other is dividing by the tile footprint rather than the repeat cell. A tile plus its joints occupies more floor than the tile does, and at wide joints on small tile the difference is large.

Frequently asked questions

How much area does a 25 lb bag of grout cover?

It depends entirely on the tile and joint, which is why the bag gives a range. On 12x24 tile with 1/8 inch joints a 25 lb bag covers several hundred square feet; on 2x2 mosaic with 1/4 inch joints the same bag covers a small fraction of that, because mosaic has many times more joint per square foot. Put your own tile size and joint into the calculator above for the figure that applies to your floor.

How much grout do I need per square foot?

For most floor tile at a normal joint it is well under a pound per square foot — the figure is small, which is why people are surprised by how far a bag goes. Small mosaic with wide joints is the exception and can use several times more. The calculator above reports pounds per square foot for your exact tile alongside the coverage.

Does joint depth change the coverage?

Directly and proportionally. Joint depth is normally the tile thickness, because a properly packed joint is full. Double the tile thickness and you double the grout. This is why large-format porcelain at 3/8 inch thick uses noticeably more grout than a 1/4 inch ceramic wall tile of the same face size.

Why does my bag's coverage figure differ from this chart?

Because the bag knows its own density and this chart assumes a typical one. Manufacturers also differ on whether their stated coverage already includes waste. The geometry is the same in both cases — if the two figures are close, the calculation is sound; if they are far apart, the bag is the one to follow, since it is the product you are actually mixing.

How much extra grout should I buy?

Around ten percent. Grout is lost in the bucket, on the float and in the mixing, and running out mid-floor is worse than a spare bag: a second batch mixed on a different day, possibly from a different production lot, can dry a visibly different shade. Mix full bags where you can for the same reason.

Is epoxy grout coverage different?

Yes — epoxy is denser, so the same joint volume weighs more, and epoxy is usually sold by the unit rather than by the pound. Work in volume rather than weight when comparing an epoxy kit against a cement bag, since the joint volume is the figure the two have in common.

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Last updated: August 26, 2026 · Reviewed by the Smart Tile Calculator editorial team