Grout Calculator

Calculate how much grout you need based on tile size, joint width, and area coverage.

Results

Visualization

How It Works

Grout fills the joints between tiles. The amount depends on tile size, thickness, and joint width. Smaller tiles and wider joints need more grout.

The Formula

Grout Volume = Num Tiles x (Tile Perimeter) x Joint Width x Tile Thickness / 2

Variables

  • Tile Perimeter — 2 x (tile length + tile width) in inches
  • Joint Width — Space between tiles, typically 1/8" to 1/2"
  • Tile Thickness — How thick the tile is (determines grout depth)

Worked Example

120 sq ft of 12"x12" tiles with 1/8" joints and 3/8" thick tiles needs about 5 lbs of grout.

Practical Tips

  • Unsanded grout is for joints 1/8" or narrower; sanded grout for wider joints.
  • Mix only what you can use in 30 minutes — grout sets quickly.
  • Epoxy grout is more expensive but resists stains and moisture.
  • Seal cement-based grout 2-4 weeks after installation.

Last updated: March 15, 2026 · Reviewed by the FlooringCalcs Editorial Team