Work out plaster sand and cement instantly with clear inputs, formula shown and shareable results.
Plaster volume is area times thickness, uplifted for the generous wastage plastering involves: droppings, over-thickness and material left in the mixer. A dry volume factor of 1.27 converts to loose material, which is then split by the mix ratio and the cement share turned into 50 kg bags.
Wet volume
m³ = area x thickness x (1 + wastage)
Materials
Dry = wet x 1.27; cement bags = dry / (1 + sand parts) x 1440 / 50
m³ = area x thickness x (1 + wastage). Plaster volume is area times thickness, uplifted for the generous wastage plastering involves: droppings, over-thickness and material left in the mixer.
Material falls off the trowel and the wall, corners need building out and the specified thickness is a minimum, so the average applied thickness is always greater than nominal.
This calculator takes 4 inputs: Area to plaster, Plaster thickness, Plaster mix, Wastage allowance. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.