How to Calculate How Much Tile Grout You Need

Grout needed (kg) = (Tile width + Tile height) / (Tile width x Tile height) x Joint width x Tile depth x Density x Area Simplified formula used by most tile manufacturers: Grout (kg) = Area (m2) x ((W + H) / (W x H)) x J x D x 1.7 W = tile width (mm) H = tile height (mm) J = grout joint width (mm) D = tile thickness (mm) 1.7 = average density of grout (kg/litre) Example: 600mm x 300mm tiles, 3mm joint, 10mm thick, 12 m2 area: = 12 x ((600+300)/(600x300)) x 3 x 10 x 1.7 = 12 x (900/180,000) x 3 x 10 x 1.7 = 12 x 0.005 x 3 x 10 x 1.7 = 12 x 0.255 = 3.06 kg

Add 10-15% waste to account for: - Excess applied then wiped off - Grout left in bucket during mixing - Final joint touching-up Example calculation completed: 3.06 kg needed + 15% waste = 3.06 x 1.15 = 3.52 kg Grout sold in: 1 kg, 2.5 kg, 5 kg bags Buy: 1 x 5 kg bag (covers with buffer for future repairs) Note: keep a small amount in the original sealed bag for future crack repairs. Colour-matching dried grout is very difficult if you need to re-grout a patch.

Joint width determines grout type: Unsanded grout: joints up to 3mm wide Wall tiles, natural stone (sanded grout can scratch polished surfaces) Sanded grout: joints 3mm and wider Floor tiles, most ceramic/porcelain applications More durable, less prone to cracking in wider joints Epoxy grout: Joints 2-12mm, wet rooms, commercial kitchens Highly stain- and chemical-resistant More expensive and harder to apply than cement-based grout Not needed for most domestic tiling