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.
Open CalculatorRelated Calculators
UKUK Building Regulations
References & Sources
Standards Cited
- BS 5385-3 — Wall and Floor Tiling — Code of Practice for the Design and Installation of Ceramic and Mosaic Tiling
Defines grout joint widths and application standards for UK tile installations - BS EN 13888 — Grout for Tiles — Definitions, Requirements, Evaluation of Conformity
Classifies grout types (CG1, CG2, RG) and performance requirements
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: BS 5385-3 / TCNA Handbook - Grout weight:
groutKg = groutVolumeLitres × coverageKgPerLitre
Source: Manufacturer coverage rates
Key Assumptions
- Grout density approximately 1.6 kg per litre (unsanded) — Manufacturer data (Mapei, BAL, Weber)
- Standard grout joint width 2-3mm for wall tiles, 3-5mm for floor tiles — BS 5385-3