About this calculator
Grout depends on tile size and joint width far more than on area. This works it out from the joint volume.
How it’s calculated
Grout volume = area × (tile length + tile width) ÷ (tile length × tile width) × joint width × joint depth. Weight = volume × about 1.6 kg/L.
Worked example
With these inputs:
- Measure by
- Length × width
- Length
- 15 ft
- Width
- 12 ft
- Tile width
- 12 in
- Tile length
- 12 in
- Tile thickness (joint depth)
- 0.375 in
- Joint width
- 0.125 in
- Bag size
- 25 lb
- Waste allowance
- 10%
the result is:
- Grout needed
- 13 lb
- Joint volume
- 0.1 cu ft
Tips from the trade
- Small mosaics use several times more grout per area than large tiles.
- Use sanded grout for joints wider than ⅛"; unsanded for narrower ones.
Results are estimates for planning and pricing. Check quantities against your drawings, the manufacturer’s data and local building codes before ordering.