Grout consumption chart (kg per 10 m²)
Estimates for 10 square metres of tiling. Scale for your area: 5 m² needs half the amount shown, and 25 m² needs two and a half times as much.
| Tile | Thickness | Joint | Sanded | Unsanded |
|---|---|---|---|---|
| 100×100 mm | 6 mm | 2 mm | 4.0 kg | 3.3 kg |
| 75×150 mm metro | 8 mm | 2 mm | 5.4 kg | 4.4 kg |
| 200×200 mm | 8 mm | 3 mm | 4.0 kg | 3.3 kg |
| 300×300 mm | 10 mm | 3 mm | 3.4 kg | 2.8 kg |
| 300×600 mm | 10 mm | 3 mm | 2.5 kg | 2.1 kg |
| 600×600 mm | 10 mm | 3 mm | 1.7 kg | 1.4 kg |
| 600×1200 mm | 10 mm | 2 mm | 0.8 kg | 0.7 kg |
Small tiles need far more grout than large ones because there are many more joints per square metre. With the same joint and thickness, 100×100 mm tiles need six times the grout of 600×600 mm tiles.
The metric grout formula
Grout consumption per square metre is the volume of the joints:
kg/m² = (L + W) ÷ (L × W) × joint width × joint depth × density
L and W are the tile length and width in mm, the joint depth is the tile thickness in mm, and the result before density is in litres per m². Sanded (wide-joint) cement grout weighs about 1.7 kg per litre, and unsanded (fine) grout about 1.4 kg per litre.
Worked example: 300×300 mm tiles
Tiles are 300×300 mm and 10 mm thick, with 3 mm joints, over 10 m².
- Joint length per m²: (300 + 300) ÷ (300 × 300) = 0.00667 per mm.
- Litres per m²: 0.00667 × 3 × 10 = 0.2 L/m².
- kg per m²: 0.2 × 1.68 ≈ 0.34 kg/m².
- Total: 0.34 × 10 m² ≈ 3.4 kg, or about 3.7 kg with 10% extra.
Choosing a joint width
- 2 mm: common for rectified porcelain, whose edges are ground to a precise size.
- 3 mm: a common all-round choice for wall and floor tiles.
- 5 mm and wider: for non-rectified, rustic, or handmade tiles that vary in size.
The tile manufacturer's recommended joint width takes priority. Joint width affects grout directly: going from 2 mm to 4 mm doubles the amount you need.
Sanded, unsanded, and grout labels outside the US
"Sanded" and "unsanded" are American terms. In the UK and Europe, grout is usually labelled by the joint widths it suits, such as "for joints 1–6 mm" or "wide joint". The rule is the same either way: use a fine grout for joints under 3 mm and a wide-joint (sanded) grout for 3 mm and wider. The calculator recommends one based on your joint width.
European grouts are also classified under EN 13888: CG1 is a standard cement grout, CG2 is an improved cement grout (often with reduced water absorption and higher abrasion resistance), and RG is a reaction-resin (epoxy) grout. See sanded vs. unsanded grout for more.
Using a specific brand
This calculator works for any cement-based grout, whether from Mapei, Kiesel, PCI, Ardex, Sopro, or a store brand. Densities vary slightly between products, so if the technical data sheet for your grout lists a consumption figure in kg/m² for your tile size and joint, use the higher of the two numbers. Grout is commonly sold in bags or tubs from about 2.5 kg to 25 kg: divide your total by the bag size and round up.