The Grout Calculator
Contractors Actually Use
Enter your tile size, joint width, and area — get the exact number of bags you need. Works with Mapei, Laticrete, Custom, and every major brand.
Compatible with all major brands
About This Tool
Why Use a Grout Calculator?
Buying too little means a second trip to the store mid-project. Too much is wasted money. This calculator gives you the precise amount — down to the bag.
What Is Grout Coverage?
Grout coverage is the area one unit of grout can fill, based on tile dimensions and joint width. Larger tiles need less grout per sq ft; wider joints need more.
How the Formula Works
We use the tile industry standard: joint volume = (tile perimeter ÷ tile area) × joint width × joint depth. This gives the exact volume of grout needed per square foot.
Who Should Use This
Tile contractors estimating material costs, homeowners doing bathroom or kitchen remodels, and project managers calculating supply orders across multiple rooms.
Important Notes
Always buy 10–15% extra for waste and future repairs. Grout is mixed by lot — buying the same color later may not match exactly. Our waste toggle handles this automatically.
Free Tool
Grout Calculator
Fill in your project details and get instant results in bags, pounds, and estimated cost.
Grout Coverage Calculator
Supports all brands · Sanded & unsanded · Metric & imperial
Step by Step
How to Calculate Grout Coverage
The grout coverage formula used by tile professionals — simplified into four steps.
Measure Your Area
Calculate total square footage: length × width for floors, or width × height for walls. Add all surfaces together.
Select Tile Size & Joint Width
Larger tiles mean fewer joints per sq ft. Wider joints hold more grout. Both dramatically affect how many bags you need.
Choose Your Brand
Each brand has different coverage rates per bag (typically 25 lb). Our calculator adjusts automatically for Mapei, Laticrete, and others.
Add Waste Buffer
Always buy 10–15% more than calculated. Cutting tiles, mixing errors, and future repairs require reserve material.
Reference Data
Grout Coverage Chart by Tile Size
Approximate coverage in sq ft per 25 lb bag of sanded grout at a 3/16" joint width.
| Tile Size | 1/8" Joint | 3/16" Joint | 1/4" Joint | 3/8" Joint |
|---|---|---|---|---|
| 2×2 | ~18 sq ft | ~12 sq ft | ~9 sq ft | ~6 sq ft |
| 4×4 | ~36 sq ft | ~24 sq ft | ~18 sq ft | ~12 sq ft |
| 6×6 | ~55 sq ft | ~36 sq ft | ~27 sq ft | ~18 sq ft |
| 12×12 | ~110 sq ft | ~73 sq ft | ~55 sq ft | ~36 sq ft |
| 12×24 | ~130 sq ft | ~87 sq ft | ~65 sq ft | ~43 sq ft |
| 18×18 | ~165 sq ft | ~110 sq ft | ~82 sq ft | ~55 sq ft |
| 24×24 | ~220 sq ft | ~146 sq ft | ~110 sq ft | ~73 sq ft |
| 2" Hex (mosaic) | ~15 sq ft | ~10 sq ft | ~7 sq ft | ~5 sq ft |
Sanded vs. Unsanded Grout: Which Do You Need?
Sanded grout contains fine silica sand, making it stronger and resistant to shrinkage in joints wider than 1/8" (3mm). It's used for most floor tiles, large-format tiles, and high-traffic areas.
Unsanded grout is smoother and used for narrow joints under 1/8". It's preferred for polished marble, glass tile, and delicate surfaces that would be scratched by sand particles.
Epoxy grout is a third category — extremely durable and stain-resistant, it's used in commercial kitchens, pools, and areas exposed to chemicals. Coverage rates differ significantly; epoxy is sold in quarts or gallons rather than pounds.
Read More →How Much Grout Do I Need per Square Foot?
A 12×12 tile with a 3/16" sanded joint requires approximately 0.34 lbs of grout per square foot. That means a 25 lb bag covers roughly 73 square feet — but this changes dramatically with tile size and joint width.
For mosaic tiles (2" hex), coverage drops to about 10 sq ft per bag because the many small tiles create a much higher perimeter-to-area ratio, filling more joints per square foot.
Always recalculate when changing tile sizes or brands. Our calculator does this instantly — no spreadsheet needed.
Brand Guide
Grout Calculator by Brand
Each brand has different bag sizes and coverage specs. Here's what you need to know.
Mapei Grout Calculator
Mapei is the world's largest tile adhesive manufacturer. Their Keracolor and Ultracolor Plus grouts come in 25 lb bags with ~73 sq ft coverage at standard 12×12 / 3/16" joint.
- Keracolor S — sanded, 40+ colors
- Ultracolor Plus FA — fast-setting, efflorescence-resistant
- Kerapoxy — epoxy, commercial-grade
Laticrete Grout Calculator
Laticrete PermaColor Select and Spectralock Pro are premium options favored by commercial tile contractors. Coverage rates are similar to Mapei but bag sizes may vary by retailer.
- PermaColor Select — 40 colors, polymer-modified
- Spectralock Pro — epoxy, LEED credits, stain-proof
- 1776 Grout — historic restoration specialist
Custom Building Products
Custom Building Products (CBP) offers Polyblend and Prism grouts. Prism is a single-component grout that works as both sanded and unsanded depending on joint width.
- Polyblend Plus — standard sanded & unsanded
- Prism — all-in-one, 40 colors
- Fusion Pro — single component, no mixing
Ardex Grout Calculator
Ardex FL and WJ 50 are professional-grade grouts used in demanding commercial and residential projects. Known for rapid setting and superior color consistency.
- Ardex FL — fine grout, narrow joints
- Ardex WJ 50 — wide joint sanded
- Ardex FG 8 — epoxy grout for wet areas
Related Resources
Complete Tile & Grout Guides
Everything you need to plan, calculate, and execute your tile project from start to finish.
How Much Grout Do I Need? Complete Guide for Any Project
Step-by-step guide covering floors, walls, showers, and backsplashes.
Mapei vs Laticrete Grout: Which Is Better in 2025?
Honest comparison of coverage, color selection, price, and performance.
Grout Joint Size Chart: What Width for Each Tile Type?
Industry recommendations for every tile format from mosaic to large slab.
Sanded vs Unsanded Grout: The Complete Contractor's Guide
When to use each type, common mistakes, and brand recommendations.
Shower Tile Estimator: How to Calculate Grout for a Shower
Includes walls, floor, niche, and bench — with a downloadable checklist.
Grout Color Chart: How to Choose the Right Color
Contrast vs. blend, light vs. dark, and how to avoid common color mistakes.
Thinset Calculator: How Much Mortar Do I Need?
Calculate thinset and mortar for floor and wall tile installations.
Laticrete PermaColor vs Spectralock: Full Comparison
Coverage, price, installation difficulty, and when to choose each.
How to Mix Grout: Step-by-Step for Perfect Results
Ratios, consistency tests, and how to avoid the most common mixing errors.
FAQ
Frequently Asked Questions
Real questions from contractors and homeowners about grout calculations and coverage.
I've set tile on 400k+ sq ft of residential and commercial projects. Every calculator and guide on this site is based on manufacturer data and verified against real job outcomes — no guesswork.
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