Grout joint width and layout
The right grout joint width is set by the tile, not by taste alone. ANSI A108.02 requires joints at least three times the actual size variation of the tile and never under 1/16 inch. From there, look, grout type and layout decide the final number.
Use the joint width calculator with measurements from your own tile, then read the guides below for the details that affect strength, cleaning and appearance.
Grout Joint Width Guide: How Wide Should Grout Lines Be?
How to set grout joint width from tile tolerances, layout and grout type, with a width table for common tile formats.
Minimum Grout Joint Width: The ANSI 3x Rule and 1/16 Inch Floor
The ANSI A108.02 rule for minimum joint width, how to measure tile size variation, and why joints set too tight fail.
Narrow Grout Joints (1/16 to 1/8 Inch): Tiles, Grouts and Technique
When 1/16 to 1/8 inch grout joints work, which grout fills them, how to pack them fully, and the lippage tradeoff.
Wide Grout Joints (1/4 Inch and Up): Maximum Widths and How to Fill
Maximum grout widths by product type, the shrinkage risks of wide joints, and filling methods for quarry, saltillo, stone and rustic tile.
Rectified Tile Grout Lines: Joint Width, Warpage and Offset Rules
What rectified tile is, how warpage and substrate flatness limit joint width, and why large tiles need a 33 percent maximum offset.
Uneven Grout Lines: Causes, Prevention and Fixes After Install
The main causes of crooked or varying grout lines, how to prevent them during layout and setting, and realistic fixes afterward.
Grout Joint Depth: How Deep Grout Should Be and Why It Matters
How deep grout needs to be, how to keep joints clear of thinset, how much to remove when regrouting, and how depth changes strength and material use.
Caulk vs Grout: Where Movement Joints Go and Which Sealant to Use
Which tile joints should be grout and which must be flexible sealant, with EJ171 spacing rules, sealant choices and how to build a joint that lasts.
Explore other guides
Grout Basics
What grout is, what it does, what it cannot do, how long it lasts and how to handle it safely.
Grout Science
The chemistry and physics behind curing, shrinkage, color, porosity and strength.
Grout Types
Every grout family, the standards behind them and how to choose the right one.
Comparisons
Head-to-head matchups with side-by-side tables and a clear recommendation.
Grout by Tile Type
Grout choice, joint width and pitfalls for each tile material.
Grout by Location
Where the tile lives changes the right grout: wet, hot, outdoor, submerged or commercial.
How to Grout
Mixing, floating, sponging, haze removal and curing, done the way pros do it.
Grout Problems
Symptom-first diagnosis: what you see, what causes it and how to fix it.
Repair and Regrouting
Patch, remove and regrout correctly, and know when the problem is below the grout.
Cleaning and Stains
Safe cleaning methods, the right chemistry for each soil, and stain-by-stain fixes.
Sealing Grout
Which grouts need sealing, which sealer to use, how to apply it and how to test it.
Grout Tools
Calculators and interactive tools for planning, buying and troubleshooting grout.
Research and Data
Original reference tables and analysis computed from first principles.