About This Calculator
This calculator estimates the amount of grout needed for tile installations based on tile size, grout line width, and grout depth. Smaller tiles require more grout per square metre due to the higher density of grout lines.
Recommended Grout Widths
| Tile Type | Grout Width |
|---|---|
| Rectified / precision-cut | 2-3 mm |
| Standard floor tiles | 3-5 mm |
| Natural stone / handmade | 5-10 mm |
| Mosaic tiles | 2-3 mm |
Tips
- • Use unsanded grout for joints under 3mm, sanded for wider joints
- • Grout depth should be at least 2/3 of the tile thickness
- • Allow 10% wastage for standard installations
- • Buy from the same batch to ensure colour consistency
Ready to Calculate?
Enter your tile area and grout joint dimensions to get quantities.
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NAIBC / IRC codes
References & Sources
Standards Cited
- ANSI A108/A118 — American National Standards for Installation of Ceramic Tile
Defines grout joint widths and application methods for various tile types - TCNA Handbook — Tile Council of North America — Handbook for Ceramic, Glass, and Stone Tile Installation
Industry standard for grout selection, joint widths, and coverage rates
Formulas Used
- Grout line length per m²:
groutLength = (tileLength + tileWidth) / (tileLength × tileWidth)
Source: Tile geometry — All dimensions in metres. Accounts for shared grout lines between adjacent tiles. - Grout volume per m²:
groutVolume = groutLineLengthPerM2 × groutWidth × groutDepth
Source: ANSI A108/A118 / TCNA Handbook - Grout weight:
groutKg = groutVolumeLitres × coverageKgPerLitre
Source: Manufacturer coverage rates
Key Assumptions
- Grout density approximately 1.6 kg per litre (unsanded) — Manufacturer data (Bostik, Custom, Prism)
- Standard grout joint width 3mm (1/8") for rectified tiles, 5mm (3/16") for natural-edge tiles — TCNA Handbook