Plaster Sand And Cement Calculator

Work out plaster sand and cement instantly with clear inputs, formula shown and shareable results.

About Plaster Sand And Cement Calculator

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.

Formulas

Wet volume

m³ = area x thickness x (1 + wastage)

Materials

Dry = wet x 1.27; cement bags = dry / (1 + sand parts) x 1440 / 50

Worked example

With the default values below, Plaster Sand And Cement Calculator returns Cement required of 8.4. Change any input above and every figure here is recalculated in your browser.

Inputs used

Area to plasterminimum 0.1 m²: 100 m²
Plaster thicknessminimum 3 mm: 12 mm
Plaster mixone of 1 : 4 cement to sand, 1 : 5 cement to sand, 1 : 6 cement to sand: 1 : 5 cement to sand
Wastage allowanceaccepts 0–40 %: 15 %

Results

Cement required: 8.4 bags
Sand required: 1.461 m³
Wet plaster volume: 1.380 m³
Dry material volume: 1.753 m³

Step by step

1Values used
2Wet volume
3Materials
4Cement required= 8.4 bags
5Sand required= 1.461 m³
6Wet plaster volume= 1.380 m³
7Dry material volume= 1.753 m³

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is the Plaster Sand And Cement figure worked out?

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.

Why is plaster wastage so high?

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.

What values do I need to enter?

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.