Estimate approximate grout volume or purchase bags for rectangular tile layouts using tile size, joint width and depth, manufacturer coverage, yield, waste, and cost.
Geometry mode models a repeating rectangular tile-and-joint module. Manufacturer coverage mode instead uses the product coverage or mixed-volume yield you enter.
Waste is applied once to base volume or exact bag equivalents before purchase quantities are rounded upward.
(tile length + joint width) × (tile width + joint width)(module area − tile area) ÷ module areasurface area × joint fraction × joint depthbags = ceiling((area ÷ coverage per bag) × (1 + extra percentage ÷ 100))A 200 ft² surface with manufacturer coverage of 50 ft² per bag needs 4 base bags; with 10% extra, buy 5 bags.
A 1.8 ft³ base requirement with 10% extra becomes 1.98 ft³. At 0.2 ft³ per bag, buy 10 bags.
A zero-width joint produces zero geometric grout volume.
Manufacturer coverage is normally the strongest purchase-planning basis. The initial 50 ft²-per-bag value is an editable example, not a universal tile-grout yield.
Grout depth is not automatically assumed to equal tile thickness; use the provided convenience button only when that is your chosen assumption.
Smaller repeated tiles generally create a larger joint fraction for the same surface area.
This calculator concerns grout for rectangular tile joints, not structural masonry grout. The modular calculation is transparent but approximate and can slightly overstate outer boundary joints.
Mesh spacing and irregular shapes can reduce accuracy. Use manufacturer coverage for irregular tile in this version.
Bag weight alone does not determine mixed yield because density and formulation vary. Product coverage also varies with tile dimensions and joint width and depth, so replace the editable starting value with documentation for the selected product.
The calculator does not choose grout type, color, sanded or unsanded product, epoxy or cement grout, joint requirements, or installation method.
Use the tile-joint geometry estimate or verified manufacturer coverage, add your selected allowance once, and round bags upward.
Smaller tiles usually create more joint area per square foot and therefore use more grout.
A wider joint increases the repeated joint fraction and estimated grout volume.
Enter the intended filled depth from your installation details; it is not automatically the full tile thickness.
Yes. Manufacturer coverage is the preferred practical purchase basis when available.
No. Enter documented area coverage or mixed-volume yield.
No. Product suitability depends on tile, joint, exposure, and project requirements.
No. Thinset or tile adhesive is a separate material.
MAPEI’s tile-grout estimator uses tile dimensions, joint width, area, and product density, and notes that jobsite factors can change consumption.