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Plaster Calculator — Free Online Calculator

Estimates the quantity of plaster mix needed to finish walls.

What is it?

The plaster and filler calculator works out how many bags you need to level walls and ceilings. Consumption depends on the layer thickness, the type of mix, and how uneven the surface is.

Formula

Kg = area × layer thickness (mm) × consumption (kg/m² per mm) Base plaster: ~1.3 kg/m² per mm. Finishing filler: ~1.0–1.2 kg/m² per mm. Bags = kg ÷ 25, rounded up.

Example

30 m² of walls, average plaster layer 15 mm. Consumption: 30 × 15 × 1.3 = 585 kg ≈ 24 bags of 25 kg. Finishing filler at 1–2 mm: 30 × 1.5 × 1.1 = 49.5 kg ≈ 2 bags.

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