Tile Grout Volume
Calculator

It calculates the total volume of the grout lines (based on tile size, grout line width, and grout depth equal to tile thickness) across your tiled area, since grout only fills the gaps between tiles, not the full floor or wall area.

Grout volume scales with line width, so doubling the grout line width from 1/8 inch to 1/4 inch roughly doubles the grout volume needed for the same tiled area, since you're filling twice as much gap space between the same number of tiles.

Yes, larger tiles have fewer total grout lines for the same area since there are fewer tile boundaries, so a room tiled with 24-inch tiles needs meaningfully less grout than the same room tiled with 12-inch tiles at the same grout line width.

The volume calculation is the same for both; the choice depends on grout line width instead — unsanded grout is used for narrow lines under 1/8 inch, while sanded grout is used for wider lines since the sand prevents shrinking and cracking in larger gaps.

Grout depth in the joint matches the tile thickness, since grout fills the full height of the gap between tiles down to the substrate, so thicker tiles (like natural stone) require noticeably more grout volume per linear foot of joint than thin ceramic tiles.