How to Calculate Tile Grout

Tile grout manufacturers calculate grout coverage rates based on the tile's length, width and thickness, the size of the grout joint and the specific gravity of the grout.

Coverage chart recommendations typically underestimate coverage to allow for waste.Coverage chart recommendations typically underestimate coverage to allow for waste.
Manufacturers perform the calculations for builders, organize the results in a chart and print the chart on grout packaging. To estimate your project's grout requirements, you must compare your tile's dimensions and the width of your grout line to the manufacturer's coverage chart and divide the estimated coverage per bag by the overall size of the project.

Measure the length and width of the space that you are tiling with a tape measure. Multiply the length by the width to determine the square footage of the project. Record the total square footage on paper.

Measure the length and width of a tile with the tape measure. Record the length and width of the tile on paper. Measure the thickness of the tile with calipers or a ruler and record the dimension on paper.

Determine the width of your grout line. Grout joint width varies according to tile type. For example, natural stone tiles typically require thin joints and saltillo tiles require large joints. Consult tile manufacturers, tile retailers, contractors or designers for assistance. Record the joint width on paper.

Locate your tile's size in the tile size column on the grout manufacturer's coverage chart. Locate the row on the chart that represents your grout joint's width. Find the box at the intersection of tile size column and joint width row. The value in this box represents your project's grout coverage per bag in square feet.

Divide the square footage of your project by the coverage in square feet per bag. The result of the division represents the amount of bags required to complete the project.

Things You Will Need

  • Tape measure
  • Paper and pencil
  • Calipers or ruler


  • If your estimation results in a fractional bag, round up to ensure complete coverage.

About the Author

Based in Hawaii, Shane Grey began writing professionally in 2004. He draws on his construction experience to write instructional home and garden articles. In addition to freelance work, Grey has held a position as an in-house copywriter for an online retailer. He holds a Bachelor of Arts in theater arts from Humboldt State University.