What does this tool do?
Grout fills the joints between tiles, so its volume depends on joint width, joint depth and the perimeter of each tile. This calculator computes the joint volume per square foot, converts it to weight and rounds up to 25 lb bags.
The Formula
Grout (lb) = Area × 144 × (Tile L + Tile W) ÷ (Tile L × Tile W) × Joint × Depth ÷ 1,728 × 100Frequently Asked Questions
How much grout do I need per square foot?
For 12 × 12 tile with 1/8 in joints, plan on roughly 0.07 lb per sq ft, or about 8 lb for 120 sq ft.
Does tile size change grout use?
Yes. Smaller tiles mean more joint length per square foot and therefore more grout.