Grout Calculator UK 2026
Instantly calculate the exact amount of grout needed for your tiling project. Enter your tile dimensions, joint width, and area to get precise kg, litre, and bag estimates.
Tiling Specifications
Enter your tile and joint details to calculate grout quantity
The depth of the grout joint should match the full thickness of the tile.
Standard joints are 2-3mm for rectified tiles, and 3-5mm for pressed edge tiles.
Standard cementitious grout is approx. 1.6 kg/L. Epoxy grout is approx. 1.7 – 1.8 kg/L.
Add 5-10% for standard cuts, or up to 20% for complex patterns like herringbone.
Grout Quantity Estimate
Weight, volume, and bag requirements for your project
Enter your tile and area details above and click Calculate Grout Needed to see your exact requirements.
Common Tile Sizes & Joint Widths
Recommended grout joint widths for various tile types. Always follow the tile manufacturer’s specifications for the best results.
| Tile Type | Common Size (mm) | Recommended Joint | Typical Application |
|---|---|---|---|
| Mosaic / Mesh Mounted | 20 × 20 | 2 – 3 mm | Feature walls, wet rooms, floors |
| Small Format | 100 × 100 | 2 – 3 mm | Kitchen splashbacks, period properties |
| Standard Square | 300 × 300 | 3 – 4 mm | Bathroom floors, utility rooms |
| Large Format (Rectified) | 600 × 600 | 2 – 3 mm | Open plan living, modern bathrooms |
| Wood Effect Planks | 1200 × 200 | 2 – 3 mm | Living areas, kitchens, bathrooms |
| External Paving | 600 × 600 | 5 – 10 mm | Patios, driveways, external steps |
Grout Calculator FAQ
Everything you need to know about calculating grout quantities, joint widths, and application best practices for UK tiling projects.
The amount of grout needed per m² depends on your tile size, joint width, and tile thickness. As a rough guide, large format tiles (600x600mm) with a 2mm joint require about 0.25 kg per m², while small mosaic tiles with a 3mm joint can require up to 1.5 kg per m². Use a grout calculator for an exact figure based on your specific dimensions.
For rectified (precision-cut) tiles, a minimum joint width of 2mm is recommended. For pressed edge (cushioned) tiles, a 3mm to 5mm joint is standard. External or floor paving applications typically require wider joints of 5mm to 10mm to accommodate thermal expansion and structural movement.
Mosaic tiles have a much higher joint-to-tile ratio, meaning they require significantly more grout. To calculate, use the individual mosaic chip dimensions (e.g., 20x20mm) rather than the full sheet size. Input these small dimensions into the calculator along with your total area to get an accurate weight.
Always follow the manufacturer’s instructions, but a standard rule of thumb for cementitious grout is approximately 4 parts grout powder to 1 part clean water by volume. Mix to a smooth, lump-free paste similar to thick peanut butter. Let it slake (rest) for 5 minutes, then re-stir briefly without adding more water.
Standard cementitious grout typically takes 24 to 48 hours to dry sufficiently for light foot traffic. Full curing and chemical resistance usually take 7 to 14 days. Epoxy grout cures faster, often within 12 to 24 hours, but is highly sensitive to temperature during application.
Yes, for standard cementitious grout in wet areas (showers, bathrooms) or kitchens, applying a high-quality grout sealer is highly recommended. It prevents water ingress, reduces staining, and makes cleaning easier. Epoxy grout is naturally waterproof and stain-resistant, so it does not require sealing.