How do I calculate grout for a shower?

Measure the total square footage of tiled wall and floor surfaces separately. Showers typically use smaller tile on floors and larger tile on walls. Run the calculator twice - once for the floor and once for the walls - then add the results together and apply your waste factor.

Grout Coverage Calculator - How Much Grout Do I Need?

Q: Does grout coverage change for epoxy grout vs. cement grout?

Yes. Epoxy grouts like SpectraLock PRO are sold in kits rather than bags, and their coverage rates differ from cement-based products. The calculator accounts for this by product - select your specific Laticrete product from the dropdown and the coverage math adjusts accordingly.

Use the calculator below to find out exactly how much grout you'll need for your tile installation. Enter your tile dimensions, joint width, total square footage, and select your grout product - we'll tell you how many bags or kits to order.

Project Details

Product

Tile width (in)

Tile length (in)

Tile thickness (in)

Grout joint (in)

Total area (Sq. Ft.) Length × Width of space

Your Results

Coverage per unit

Sq. Ft.

Units needed

exact

units

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Coverage is approximate based on nominal tile size. Actual coverage varies by jobsite conditions, actual tile size, and installation method. Always verify with your Laticrete representative for large commercial projects.

How to Calculate Grout Coverage

Grout coverage depends on four variables: the size of your tile, the width of your grout joints, the depth of those joints (tile thickness), and the total square footage of your project. Larger tiles with narrow joints require significantly less grout than small mosaic tiles with wide joints.

The standard formula used in the industry is:

Bags needed = (Tile width + Tile length) ÷ (Tile width × Tile length) × Joint width × Tile thickness × Area × Coverage factor

In practice, a 12×24 tile with a 1/8" joint on a 200 sq ft floor will require far fewer bags than a 4×4 mosaic tile with a 3/16" joint on the same floor. That’s why using a calculator - rather than guessing - prevents both costly shortages and wasted material.

How Much Extra Grout Should I Order?

Always order more than your calculated amount. The standard recommendation is:

10% extra for glazed ceramic or porcelain tile - smooth, consistent surfaces
15% extra for unglazed, quarry, or natural stone tile - more porous, absorbs more grout

Our calculator applies these waste factors automatically based on your tile type selection. If you’re cutting a lot of tile around obstacles or working in an unusually shaped space, consider bumping your waste factor to 20%.

Choosing the Right Grout for Your Project

Not all grout is the same. The right grout depends on your tile type, joint width, and the demands of the installation environment.

Epoxy Grout (SpectraLock PRO, SpectraLock 2000 IG) - Epoxy grout is the most durable option available. It’s stain-resistant, chemical-resistant, and doesn’t require sealing. It’s the preferred choice for kitchen backsplashes, commercial floors, wet areas, and anywhere hygiene matters. Epoxy grout sets quickly and requires careful mixing, but for professional and high-traffic installations it’s the gold standard.

Cement-Based Grout (PermaColor, PermaColor Select) - Cement-based grouts are easier to apply, widely available, and appropriate for most residential tile projects. PermaColor and PermaColor Select offer color consistency and sanded or unsanded options depending on your joint width.

Joint Width Rules of Thumb:

Under 1/8" joint → unsanded grout
1/8" to 1/2" joint → sanded grout
Over 1/2" joint → sanded grout or grout mixed with aggregate

Grout Coverage by Tile Size - Quick Reference

Tile Size	Joint Width	Approx. Coverage per 25 lb bag
4×4	3/16"	35–45 sq ft
12×12	3/16"	95–110 sq ft
12×24	1/8"	140–160 sq ft
18×18	3/16"	130–150 sq ft
24×24	3/16"	160–185 sq ft

* Coverage varies by product. Always confirm with the specific product data sheet.

Frequently Asked Questions

It depends on your tile size and joint width. For a common 12×12 tile with a 3/16" joint, a 25 lb bag of cement-based grout covers approximately 95–110 sq ft, so one bag is usually sufficient for 100 sq ft with a small amount left over. For smaller tiles or wider joints, you may need 2–3 bags for the same area. Use the calculator above for an exact figure based on your specific tile and product.

Running short mid-project is a serious problem. Grout is mixed in batches, and color can vary slightly between bags or production lots. If you run out and buy more grout later - even the same color - you risk visible color variation in your finished floor. Always order at least 10–15% more than your calculated amount, and keep an unopened bag as a reserve for future repairs.

Yes. The calculation method is the same for floors and walls. The main difference is that wall tile is typically smaller, uses narrower joints, and may use unsanded grout. Enter your actual measurements regardless of orientation and the calculator will give you an accurate result.

Sanded grout contains fine sand aggregate and is used for joints 1/8" wide or larger. The sand adds body and prevents shrinkage cracking in wider joints. Unsanded grout is smoother and used for joints under 1/8" - it’s also preferred for polished stone and glass tile where sanded grout could scratch the surface.

Yes. Epoxy grouts like SpectraLock PRO are sold in kits (Part A resin + Part B hardener + Part C powder) rather than bags, and their coverage rates differ from cement-based products. The calculator accounts for this by product - select your specific Laticrete product from the dropdown and the coverage math adjusts accordingly.

Measure the total square footage of tiled wall and floor surfaces separately. Showers typically use smaller tile on floors (mosaic or 4×4) and larger tile on walls (12×24 or larger). Run the calculator twice - once for the floor and once for the walls - then add the results together and apply your waste factor.

Cement-based grout should be sealed 48–72 hours after installation and resealed annually in wet or high-traffic areas. Epoxy grout (SpectraLock, SpectraLock 2000 IG) does not require sealing - it’s inherently stain and moisture resistant. PermaColor Select NS is a non-sanded epoxy-enhanced cement grout that also offers improved stain resistance compared to standard cement grout.

Shop Laticrete Grout at Wholesale Prices

FlooringMarket.com carries the full line of Laticrete grout products including SpectraLock PRO, PermaColor, and PermaColor Select - shipped directly to your door at wholesale pricing.