Construction

Grout Calculator

Estimate the grout needed to fill the joints between your tiles.

Tiled area

Tile length

Tile width

Tile thickness

Joint width

Calculated Output

Grout needed 8.775

Grout per ft² (lb/ft²) 0.0731

Formula: vol/ft² = 144 × (L+W)/(L×W) × joint × depth

Step-by-Step Breakdown

1. Values used:

2. Tiled area = 120

3. Tile length = 12

4. Tile width = 12

5. Tile thickness = 0.375

6. Joint width = 0.125

8. Grout needed = 8.775

9. Grout per ft² = 0.0731lb/ft²

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The math behind it

Per square foot, joint volume ≈ 144 × (tileL + tileW) ÷ (tileL × tileW) × joint width × joint depth (in³).

Multiply by grout density (~0.065 lb/in³) for weight, then by the tiled area.

120 ft² of 12×12 in tiles, 3/8 in thick, 1/8 in joints ≈ 0.59 lb/ft² → ~71 lb of grout.

Why does joint width matter so much?

Grout volume scales directly with joint width and depth — doubling either roughly doubles the grout.