Tile Countertop Layout and Grout Calculator
Calculate the number of tiles, cut tiles, and grout required for your countertop tiling project.
Formulas Used
Tile Pitch = Tile Dimension + Grout Joint Width
Tiles Along Length = ⌈(Countertop Length + Grout Joint) / PitchL⌉
Tiles Along Width = ⌈(Countertop Width + Grout Joint) / PitchW⌉
Total Grid Tiles = Tiles Along Length × Tiles Along Width
Cut Tiles = tiles in the last column + tiles in the last row − 1 corner (if both edges are cut)
Tiles to Purchase = ⌈Total Grid Tiles × (1 + Waste% / 100)⌉
Grout Volume (horizontal joints) = (Tiles Along Width − 1) × Countertop Length × Joint Width × Joint Depth
Grout Volume (vertical joints) = (Tiles Along Length − 1) × Countertop Width × Joint Width × Joint Depth
Grout Weight (volume) = Total Grout Volume (ft³) × 100 lb/ft³
Grout Weight (coverage) = Countertop Area (ft²) / Coverage (ft²/lb)
Grout to Purchase = max(volume-based, coverage-based) weight
Assumptions & References
- Tile layout uses a standard grid (no diagonal or offset patterns).
- Grout joint depth equals the tile thickness by default; adjust if setting bed is recessed.
- Unsanded grout density assumed at ~100 lb/ft³ (TCNA Handbook reference range: 90–110 lb/ft³).
- Coverage-based grout estimate uses manufacturer-supplied coverage figure (default 40 sq ft/lb for 4″ tiles with 1/8″ joints — adjust per bag label).
- Waste factor of 10% is standard for straight cuts; increase to 15–20% for diagonal or complex layouts.
- Cut tiles along edges are counted conservatively: any remainder > 0.001″ triggers a cut tile row/column.
- Grout bags are available in 10 lb and 25 lb sizes; calculator rounds up to whole bags.
- Does not account for backsplash, edge trim, or adhesive/mortar quantities.
- References: TCNA (Tile Council of North America) Handbook; ANSI A108/A118/A136 standards.