Calculator
Plastering Calculator
Calculate cement bags and sand for wall plaster — area in m² or ft², thickness in mm or inches.
Inputs
Unit system
Results
Wet plaster volume
0.12m³
50 kg cement bags
1bags
Sand required
4.51cft
How this is calculated
Formula
- Convert ft²/in → m²/m if imperial is selected
- wet_volume = area × thickness
- dry_volume = wet_volume × 1.33
- cement_m³ = dry_volume × 1 ÷ (1 + N)
- sand_cft = (dry_volume × N ÷ (1 + N)) × 35.3147
- bags = ceil(cement_m³ ÷ (50/1440))
Assumptions
- Choose Metric (m², mm) or Imperial (ft², in) for area and thickness.
- Wet volume = area × thickness (converted to SI internally).
- Dry mortar volume = wet × 1.33.
- Ratio 1:N means 1 part cement to N parts sand by volume.
- Cement bags are 50 kg (density 1440 kg/m³).