Inputs
Results
Wet Plaster Volume
0.000 m³
0.000 ft³
Dry Mortar Volume (incl. factor, wastage)
0.000 m³
0.000 ft³
Cement required
0.00 bags
0 kg
Volume share:
Sand required
0.000 m³
0.000 ft³
Adjusted for bulking/compaction: 0.000 m³
Recommended Water
0 L
0 gal
Notes: 1 m³ = 35.3147 ft³. 1 gal (US) = 3.785 L. Rounded for display.
Example Data
| Area | Thickness | Ratio | Wastage | Bulking | Wet Vol (m³) | Cement (bags) | Sand (m³) | Water (L) |
|---|---|---|---|---|---|---|---|---|
| 50 m² | 15 mm | 1:4 | 5% | 20% | 0.750 | 10.53 | 1.028 | 758 |
| 30 m² | 12 mm | 1:5 | 7% | 15% | 0.360 | 4.43 | 0.526 | 319 |
| 80 m² | 20 mm | 1:6 | 5% | 25% | 1.600 | 16.36 | 2.654 | 1178 |
Formula Used
- Wet volume
Vw = Area × Thickness(Thickness in meters). - Dry volume
Vd = Vw × DryFactor × (1 + Wastage%). - Mix split for
1 : S⇒ Cement share =Vd × 1/(1+S), Sand share =Vd × S/(1+S). - Cement weight
Wc = CementVolume × CementDensity; Bags =Wc / BagWeight. - Sand adjusted volume =
SandVolume × (1 + Bulking%). - Recommended water ≈
Wc × (w/c)litres. Convert to gallons as needed.
Default densities: Cement 1440 kg/m³; Sand 1600 kg/m³. Defaults are editable.
How to Use This Calculator
- Select units, then enter plastered surface area or use Area Assistant.
- Set plaster thickness, choose a ratio preset, or define a custom ratio.
- Adjust dry factor, wastage, bulking, densities, bag weight, and w/c if needed.
- Press Calculate to see volumes, cement bags, sand, and water required.
- Use Download CSV or Download PDF to export your results.
- Optionally hit Fill Example to load sensible demonstration inputs.
FAQs
Commonly 1:4 or 1:5 for internal walls. Richer mixes increase strength and reduce shrinkage, but mind workability and substrate condition.
Dry ingredients occupy more volume due to voids. A factor near 1.33 is typical to convert wet volume to dry mortar quantity.
Moisture and handling can change sand volume. The bulking percentage compensates for this, increasing practical sand volume needed on site.
They are engineering estimates. Site practices, substrate absorption, and workmanship influence actual consumption. Consider adding contingency beyond wastage allowance.
Yes. Unit labels update automatically. Values are interpreted according to the currently selected unit system, with conversions handled in outputs.
Use the standard bag weight in your region. Many markets use 50 kg; others may use 40 kg or 42.5 kg equivalents.