Tile grout calculator

How to use it

1. Enter the positive installed area and choose either a declared mass rate or rectangular-joint geometry.
2. For geometry, enter actual tile length and width, filled joint depth, joint width and the exact product's bulk density; then enter your own waste.
3. Optionally add available bag masses, calculate, and compare every input with the current product instructions.

Formula

Declared mode uses area × declared mass per area. Geometry mode derives joint rate = ((tile length + tile width) ÷ (tile length × tile width)) × filled depth × joint width × bulk density, then multiplies by area. Required grout = theoretical grout × (1 + waste ÷ 100).

Example

For 10 m², 0.6 m × 0.6 m tiles, 12 mm filled depth, 5 mm joints, density 1600 kg/m³ and 10% waste: joint rate is 0.32 kg/m², theoretical grout is 3.2 kg, waste is 0.32 kg and required grout is 3.52 kg. One 5 kg bag leaves 1.48 kg. A declared 0.32 kg/m² rate gives the same material result.

Assumptions

• Geometry mode represents a regular orthogonal grid of rectangular tiles with consistently filled joints.
• Rate or density, joint measurements, waste and bag masses are explicit entries for the exact grout and application context.

Limitations

• The calculator does not choose grout type, colour, joint width, filled depth, density, water ratio or application conditions.
• Cut edges, borders, repeating patterns, roughness loss, movement or expansion joints, perimeter sealant and caulk are not modelled.
• It is not a Joint Compound seam-treatment calculator and does not check prices, stock or product suitability.