Self-Leveling Compound
Quick answer: For 20 m² of self-levelling compound at 3 mm you need about 102 kg, i.e. 5 × 25 kg bags.
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How the calculation works
Enter the area and layer thickness. The calculator multiplies consumption per millimetre of thickness by thickness and area, then rounds up to whole 25 kg bags.
Formula and assumptions
Required (kg) = area × thickness (mm) × 1.7 kg/m² per mm, rounded up. Bags = kg ÷ 25, rounded up. The 1.7 kg/m² per mm figure is an indicative value for cementitious self-levelling compounds – check the product's data sheet.
Worked example
Area 20 m², 3 mm layer: 1.7 × 3 = 5.1 kg/m². Required 5.1 × 20 = 102 kg. To buy: 5 bags × 25 kg = 125 kg (102 ÷ 25 = 4.08 → 5).
More worked examples
- Area 30 m², layer 5 mm: 1.7 × 5 = 8.5 kg/m². Needed 8.5 × 30 = 255 kg → 255 ÷ 25 = 10.2 → 11 bags (275 kg).
- Area 12 m², layer 2 mm: 1.7 × 2 = 3.4 kg/m². Needed 3.4 × 12 = 40.8 kg → 40.8 ÷ 25 = 1.6 → 2 bags (50 kg).
Consumption by layer thickness (50 m²)
| Thickness (mm) | kg per m² | kg for 50 m² | Bags of 25 kg |
|---|---|---|---|
| 2 | 3.4 | 170 | 7 |
| 3 | 5.1 | 255 | 11 |
| 5 | 8.5 | 425 | 17 |
| 8 | 13.6 | 680 | 28 |
| 10 | 17 | 850 | 34 |
What affects real consumption
- Substrate unevenness: deeper depressions use more compound.
- Substrate absorbency and primer.
- The minimum and maximum layer thickness the manufacturer allows.
Common mistakes
- Measuring the layer at the highest point only; the deepest hollows of the substrate also need filling.
- Skipping the primer, so the absorbent substrate draws water out of the compound.
- Using a thickness outside the minimum and maximum the manufacturer specifies.
- Buying exactly the calculated kilograms instead of whole bags.
Frequently asked questions
Is 1.7 kg/m² per mm right for every compound?
No – it is a common indicative value. Actual consumption depends on the product and is given in its data sheet.
How much extra should I add?
Because of unevenness and mixing losses some installers add a few percent; the calculator already rounds up to a whole bag.
How many kilograms of compound do I need per m² at 5 mm?
About 8.5 kg/m² (1.7 kg/m² per mm × 5 mm). For 30 m² that is 255 kg, or 11 bags of 25 kg.
Can I use the calculator for a thick cement screed?
Not directly. The value of 1.7 kg/m² per mm is for self-levelling compounds; thick cement screeds have a different density and should be calculated separately. Check the product data sheet.
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Publisher: Art-Visum d.o.o. · Content reviewed:
Calculations use common consumption rates and manufacturers' technical data sheets; results are estimates. Methodology · Standards · About