TileQuantCoverage math for tile, thinset and grout — before you buy.

What size grout line for 6x6 tile?

Grout joint for 6x6 tile
1/16″minimum, rectified
unsanded grout — ANSI A108.02, at least 3× the tile's facial dimension variation
6″ × 6″50% offset1/16″grout jointunsanded groutstandard · 6″ sideANSI A108.02joint width exaggerated for legibility
Recommended joint1/16″
Grout typejoints under 1/8″ take unsanded, 1/8″ and over take sandedUnsanded
ANSI absolute minimumno joint may be tighter than this, whatever the tile1/16″
Large format?any side over 15″ counts, and it changes the mortar and the offsetNo — longest side 6″
— Joint by how the tile is made —
Rectified porcelainedges ground square after firing — the tightest joints are only possible here — ANSI minimum 1/16″1/16″
Pressed (calibrated) porcelain or ceramicfired to size, so pieces differ slightly and the joint has to absorb it — ANSI minimum 1/8″1/8″
Natural stonecut to size but the material itself varies; honed stone is tighter than tumbled — ANSI minimum 1/8″1/8″
Handmade or hand-lookthe variation is the point of the tile, and the joint has to be generous — ANSI minimum 3/16″3/16″

Notes

  • 6x6. A small square, common in older bathrooms and in handmade ranges. Handmade tile can vary by a sixteenth of an inch between pieces, and the joint has to be at least three times that.
  • The rule is a multiple, not a number. ANSI A108.02 sets the joint at at least three times the actual variation in facial dimension of the tile you bought — with an absolute floor of 1/16″. That means the answer depends on the box in front of you, not on the size alone. Lay ten tiles face up, measure the smallest and the largest, and multiply the difference by three.
  • This joint takes unsanded grout. Below 1/8″, sanded grout will not pack into the joint properly and the sand can scratch polished or soft-glazed tile on the way in.
  • Under 15 inches the tile is forgiving, the substrate less so. A small tile follows a slightly uneven floor without complaint, which is exactly why an uneven floor stays hidden until the day it is tiled in something larger.
  • Tighter joints are a design choice with a cost. A 1/16″ joint reads as a continuous surface and is what makes large-format tile look like slab. It also removes every bit of tolerance you had — the layout has to be right first time, the substrate has to be flat, and the tile has to be rectified. Going from 1/16″ to 1/8″ buys back a great deal of forgiveness for very little visual change.
  • Manufacturer instructions override this page. Where the box specifies a minimum joint, that figure governs, and ignoring it is usually what voids the warranty.

6x6 tile

1/16″ minimum, with unsanded grout.

The standard is a multiple, not a number

ANSI A108.02 sets the grout joint at at least three times the actual variation in facial dimension of the tile you bought, with an absolute floor of 1/16″.

That makes it a property of the box, not of the size. Lay ten tiles face up, measure the smallest and the largest, multiply the difference by three. Rectified porcelain will give you a very small number; a handmade tile will not.

Sanded or unsanded is decided by the joint, not the tile

Under 1/8″, unsanded. At 1/8″ and over, sanded. The sand is structural — unsanded grout in a wide joint shrinks and cracks as it cures, and sanded grout in a narrow one will not pack in properly and can scratch a polished glaze going in.

Tighter joints remove your tolerance

A 1/16″ joint is what makes large-format tile read as a continuous surface. It also means the layout has to be right the first time, the substrate has to be genuinely flat, and every tile has to be the same size. Going to 1/8″ buys back a lot of forgiveness for very little visual difference.

Nearby sizes

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