Formula used
Units = ceil([project area ÷ coverage per unit] × [1 + waste ÷ 100])
Worked grout example
Grout Calculator example: 398 ft² × 1.1 = 437.8 ft² of order coverage. Dividing by 100 ft² per unit gives 4.38 units, so the purchase quantity is 5 whole units.
Package rounding and usable yield
Use the package count as a purchase check, keeping colors and batch numbers separate when the project requires visual consistency.
Grout yield is controlled by joint geometry
Tile face area alone does not determine grout use. Joint width and depth, tile dimensions, edge profile, grout type, mixing water, waste during washing, and whether movement joints remain ungrouted all affect bag coverage. Use the manufacturer's coverage table for the exact tile and joint combination as the coverage-per-unit input.
Why the label value may not match the floor or wall
Narrow mosaics have far more joint length than large-format tile; joint depth, waste during washing, and the grout's mixed yield also matter.
Questions specific to this calculation
Why can grout-bag coverage vary so much between tile joints?
Enter the tiled area that will receive grout and a coverage figure for the chosen joint width, tile size, tile thickness, and product.