The best thing to do is use the smallest grout line your particular tile will allow and get a grout that closely matches the tile.
Marble subway tile grout line.
For most granite and marble tile i install i use either 1 32 or 1 16 inch grout lines.
As a general rule floor tiles should have grout lines of 1 8 inch or larger depending on the type and size of tile.
This thickness leaves room for the natural variation in.
Most floor tiles are 8 inches by 8 inches but larger versions are available.
I try to use the smallest grout lines the tile will allow.
Grout including sealed grout tends to wear more quickly than tile and become more porous and prone to staining.
Although tile installations can be installed in groutless format the traditional method calls for grout to be placed in the joints between the tiles.
If you are going for high contrast or retro style wider grout spacing gives you the opportunity to make a statement with your grout.
Finished grout lines will vary from 1 16 to 3 16.
Grout lines for floor tiles.
This is true of man.
If smaller spacers like 1 8 are used it will accentuate the size difference of handmade tile.
Note that using the smallest grout possible will increase installation time.
In most other tile i will use 1 16 or 1 8 inch lines.
We recommend a 3 16 grout size for our ceramic tile line.
Thinner grout spacing for subway tile creates a more subtle effect and wider grout lines a more dramatic one.