TilingLab.

Grout Calculator

Find the grout weight and bags for your tile. Enter the area, tile size and joint width to compare sanded and unsanded estimates.

YOUR PROJECT
01

Measure your space

02

Tile and joints

Accepts decimals, fractions and feet with inches.

Accepts decimals, fractions and feet with inches.

Accepts decimals, fractions and feet with inches.

Accepts decimals, fractions and feet with inches.

Use the actual tile face size. Fractions such as 3/16 and feet with inches are accepted.

03

Choose your bag size

These estimates use cement grout densities. Check the chosen grout’s joint limits and coverage chart before ordering.

1 bag of sanded groutSee estimate

PLAN THE JOINTS

Tile Spacing Chart: Joint Width, Spacer Size and Coverage

The spacer matches the joint width you choose. This table uses 100 sq ft of 12 × 24 × 3/8 inch tile and includes 10% extra grout. Joint width must also suit your tile and grout instructions.

Calculated cement grout weights for one tile size
Joint and spacerGrout model usedGrout / 100 sq ft
1/16″Conventional unsanded-grout estimate2.82 lb
1/8″Conventional sanded-grout estimate5.80 lb
3/16″Conventional sanded-grout estimate8.70 lb
1/4″Conventional sanded-grout estimate11.60 lb
3/8″Conventional sanded-grout estimate17.40 lb

Grout Calculator by Tile Type

Subway starts with 3 × 6 inch tile, 5/16 inch deep joints and 1/16 inch spacing. Smaller tile puts more joint length into the same area than the large format preset.

Large format starts with 12 × 24 × 3/8 inch tile and 1/8 inch spacing. The rectangle formula uses both face dimensions.

Hexagon starts with a 2 inch distance across opposite flat sides, 1/4 inch thickness and 1/8 inch spacing. Enter the distance across flats, not corner to corner. Joint length per unit area is 2 divided by that distance.

Penny round starts with 1 inch diameter circles, 1/4 inch thickness and 1/8 inch spacing between neighboring circles. The estimate uses hexagonal packing and includes the spaces between three circles. Use individual circle dimensions, not sheet dimensions.

How Much Grout Do I Need?

Grout fills the joints; mortar bonds the tile to the substrate. Use the thinset calculator to estimate mortar bags separately.

For rectangles, joint volume per square foot is 144 × (length + width) ÷ (length × width) × joint width × depth, with lengths in inches. Multiply by your square footage, divide by 1,728 to convert to cubic feet, then multiply by grout density and 1.10 for extra material.

For the default 100 sq ft project, 12 × 24 × 3/8 inch tiles and 1/8 inch joints give 0.84375 cubic inches of grout per sq ft. At 108 lb per cubic foot: 100 × 0.84375 ÷ 1,728 × 108 × 1.10 = 5.80 lb of sanded grout.

The hexagon formula replaces the rectangle’s length factor with 2 ÷ distance across flats. Penny rounds use the uncovered fraction of a hexagonally packed circle cell: 1 − (πD²/4) ÷ [(√3/2)(D + joint width)²]. Multiply this fraction by 144 and joint depth for cubic inches per sq ft.

Grout Coverage Chart

Square feet one 25 lb bag covers, by tile size and joint width. Each column uses the conventional grout model selected for that width, assumes full-depth joints and includes 10% extra. A width only applies if your tile allows it.

Coverage per 25 lb bag, in sq ft
Tile (inches)1/16″unsanded1/8″sanded3/16″sanded1/4″sanded
3 × 6 subway5/16″ thick2661298665
12 × 123/8″ thick665323215162
6 × 24 plank3/8″ thick532259172129
12 × 243/8″ thick887431287215
24 × 243/8″ thick1330646431323

Bag Sizes and Brand Differences

Select 10 lb, 25 lb or enter the weight printed on your package. Bags round up to whole packages. For the default dimensions, one 25 lb bag of sanded grout covers 431.0 sq ft in this model.

Coverage varies by grout formulation, joint depth and application method. This calculator uses generic cement-grout density assumptions. Other brands, such as Tile Doctor and UZIN, publish their own grout calculators with different densities and package sizes. Before ordering, compare the estimate with the current coverage chart for your selected product and package size.

Manufacturer coverage per package for 12 × 12 × 3/8 in tile, 1/8 in joint
ProductPackageCoverage
Custom Building Products
Polyblend Plus Sanded Grout25 lb bag348 sq ft
Polyblend Plus Non-Sanded Grout10 lb box146 sq ft
Prism Ultimate Performance Cement Grout17 lb box348 sq ft
Fusion Pro Single Component Grout1 gal pail199 sq ft
MAPEI
Keracolor S Sanded Grout25 lb bag383 sq ft
Keracolor U Unsanded Grout25 lb bag530 sq ft
Ultracolor Plus FA25 lb bag388 sq ft

Manufacturer coverage assumes specific tile thickness and joint width. Your calculated figure uses your own inputs.

Figures are from each manufacturer's technical data sheet; check the sheet for your tile and joint size.

BEFORE YOU BUY

Grout calculator questions

How much grout do I need for 100 sq ft?

For 12 × 24 × 3/8 inch tile with 1/8 inch joints, our estimate is 5.80 lb of sanded grout, including 10% extra. Smaller tiles, deeper joints and wider joints need more grout.

How much grout per square foot?

The same 12 × 24 inch example uses 0.0580 lb per sq ft with the allowance included. Enter your actual tile size and joint width; there is no single coverage rate for every tile.

How much does grout cost per square foot?

Divide your total bag cost by the area you will grout. For example, if your bag costs $30 and your project covers 100 sq ft, the grout material cost is $0.30 per sq ft. This example price is an assumption, not a store quote; labor and other materials are separate.

Do I need sanded or unsanded grout?

The table uses conventional unsanded grout below 1/8 inch and sanded at 1/8 inch or wider as quantity models. Joint width alone does not choose a product. Check approval for your joint width, tile surface and installation location, then use that product’s coverage chart.

1/16 vs 1/8 grout lines

For the same rectangular tile, depth, area and grout density, a 1/8 inch joint uses twice the grout of a 1/16 inch joint in this model. Choose the width your tile instructions allow. Compare grout line sizes in the guide.

What size tile spacers do I need for 12x24 tile?

Match the spacer to your selected joint width: a 3/16 inch joint uses a 3/16 inch spacer. Tile face dimensions alone do not determine the required joint; check the tile instructions and the size variation in your batch.

How do I calculate grout for subway tile?

Choose the Subway tab to load 3 × 6 inch tile, 5/16 inch thickness and a 1/16 inch joint. Replace those assumptions with your tile dimensions and measured area before ordering.

Does this work for epoxy grout?

The geometry can describe the joints, but the weight and bags here use cement grout density assumptions. Use the epoxy product’s coverage calculator or data sheet for an epoxy order.

How many square feet does a 25 lb bag of grout cover?

Our formula gives 431.0 sq ft for sanded grout with 12 × 24 × 3/8 inch tiles and 1/8 inch joints, including 10% extra. At 1/4 inch joints it gives 215.5 sq ft. Coverage changes with tile size and joint depth.

Why is your result different from the bag's coverage chart?

We assume joint depth equals tile thickness and add 10% extra. Density, actual joint depth, tile edges and installation technique affect coverage. Use the specific product chart when placing your order.