Grout Calculator

Estimate how much tile grout to buy from your project area, tile size, joint width, joint depth, package size, and waste allowance. Use product label coverage when you have it, or start with a transparent generic estimate.

Reviewed and updated July 1, 2026

Use it when you want to know

Estimate bags before you buySee grout pounds, rounded package count, waste included, and optional material cost.
Handle fractions like 1/16 and 1/8Tap common joint widths instead of converting every fraction by hand.
Check mosaic and wide-joint riskGet warnings for penny tile, narrow joints, wide joints, and product-specific coverage.

Calculator

How much grout do you need?

Enter the tiled area, tile size, joint width, and joint depth. If your grout bag lists coverage for your exact tile and joint size, use the product-label override for the safest package count.

Project and tile size

Project area

sq ft

Use the tiled area after subtracting large no-tile openings.

Tile length

Tile width

Grout joint

Joint width

Tap a common fraction or enter the decimal width from your spacer.

Tile thickness

Common porcelain tile is often near 3/8 in.Joint depth

Use real joint depth if you know it.

Product and package

Grout typeType changes the generic yield estimate. Exact product coverage is better.

Waste allowance

Use 5% to 10% for many projects; mosaics may need more cushion.Package size

Label coverage override

sq ft/pkg

If the bag lists coverage for your tile, this overrides generic weight math.Price per package

Optional. Used only for material cost.

Guide

How to calculate how much grout you need

A good grout estimate starts with the actual shape of the gaps between tiles. Area alone is not enough because tile size, joint width, and depth decide how much empty space the grout must fill.

What affects grout quantity?

The biggest drivers are tile size, joint width, and joint depth. Large-format tile has fewer grout lines per square foot, while subway tile, mosaic tile, and penny tile have many more joints to fill.

Product density also matters. Cementitious, epoxy, premixed, and fine-aggregate grouts can publish different coverage for the same tile. That is why a manufacturer calculator or bag chart should override a generic estimate when you have the exact product.

Generic grout estimatevolume = ((L + W) / (L x W)) x joint width x joint depth x area

Then convert volume to pounds using the grout yield, add waste, and round up to full packages. Example: 100 sq ft of 12 x 24 tile with 1/8 in joints and 3/8 in depth uses about 5 lb with a 10% buffer under the generic cement grout estimate.

What is the difference between joint width and joint depth?

Joint width is the visible gap between tiles, often set by spacers such as 1/16 in or 1/8 in. Joint depth is how deep the grout fills between the tile edges. Tile thickness is a useful estimate, but beveled tile, mortar left in the joint, and cleanup technique can change the actual depth.

Why does penny tile use so much grout?

Penny tile and small mosaics have many small edges packed into each square foot. Even if the room area is small, the total joint length can be high. If another calculator seems low for penny tile, check whether it truly accounts for small mosaic spacing and product-specific coverage.

What should you do after calculating grout?

Check the exact grout label before buying, then estimate the rest of the project. If you are still planning tile quantity, use the backsplash tile calculator for small walls or the flooring calculator for floor area, boxes, and waste.

When should you use product coverage?

Brand calculators such as MAPEI's grout calculator and product charts are best when you already picked a grout. They account for product-specific coverage better than a generic volume estimate.

Which grout type fits your joint width?

The TCNA grout FAQ notes that cementitious grout below 1/8 in is generally unsanded, 1/8 in and larger is generally sanded, and joints above 3/8 in usually need a more heavily sanded product.

Can the calculator choose your grout joint?

Tile variation, rectified edges, calibrated edges, lippage control, and the tile manufacturer all affect the correct joint width. This calculator estimates quantity after you choose the joint.

FAQ

Grout calculator questions

How much grout do I need?

Grout quantity depends on tile size, total area, joint width, joint depth, grout type, and waste. Small tile, wider joints, and deeper joints can multiply the amount needed, so a 2 inch mosaic can require far more grout per square foot than a 12 by 24 inch tile.

How much does a 25 lb bag of grout cover?

Coverage varies heavily by tile and joint size. A 25 lb bag may cover a large area with big tile and narrow joints, but much less with penny tile, mosaic sheets, or wide joints. Use the product label or manufacturer calculator when you know the exact grout.

Do small mosaic or penny tiles need more grout?

Yes. Penny tile and small mosaics have many more grout lines per square foot than large-format tile. That is why mosaic floors and backsplashes can use several times more grout than the same area of 12 by 24 inch tile.

What grout joint width should I use?

Follow the tile manufacturer and installer guidance. Very narrow joints leave less room for tile size variation, while wider joints may need a different grout product. The calculator estimates quantity; it does not prescribe the correct joint width for every tile.

Should I use sanded or unsanded grout?

For cementitious grout, TCNA guidance generally points to unsanded grout below 1/8 inch, sanded grout at 1/8 inch and larger, and a more heavily sanded product above 3/8 inch. Modern high-performance grouts may have their own approved ranges, so check the bag.

Should grout depth equal tile thickness?

Tile thickness is a practical estimating shortcut, but the actual grout depth can be affected by tile edge shape, mortar left in joints, and cleanup. If you know the real joint depth, enter it directly.

Is epoxy grout calculated differently?

Epoxy products can have different density, package sizes, and coverage tables than cement grout. Use the epoxy manufacturer coverage when available. This calculator uses a slightly lower default yield for epoxy when no product label data is entered.

Should I buy extra grout?

Usually yes. A 5% to 10% buffer is common for normal projects, and mosaics, uneven joints, first-time DIY work, or hard-to-rebuy colors may justify buying an extra returnable package.