Calculator
Plaster mix calculator
Turns the area and average plaster thickness into an estimated material weight and number of bags.
Online calculation
Enter dimensions
Result
Result
Calculation formula
Mix = area × coverage for 10 mm × (layer thickness ÷ 10); with allowance = mix × (1 + allowance / 100); bags = ceil(with-allowance amount ÷ bag weight).
Example: For 20 m², a 15 mm layer, coverage of 8 kg/m² per 10 mm and a 10% allowance, the estimate is about 264 kg. With 25 kg bags, that is 11 bags.
Frequently asked questions
Why does the layer thickness change the result?
Coverage on a product label is tied to a stated thickness. A 20 mm layer needs roughly twice as much material as a 10 mm layer when the substrate and application method are the same.
Can I calculate an uneven wall?
Yes. Enter the average layer thickness. For large variations, guide marks or local repairs, split the surface into sections and keep a practical allowance.