Sand for Mortar/Plaster Calculator

Plan mortar and plaster mixes with precise, professional control and clarity everywhere. Switch modes, set thickness, choose ratios, and factor bulking precisely today anywhere. Get sand volumes, bag counts, densities, waste, coverage, and yield instantly computed. Export results as CSV or PDF for records.

Inputs
Load common mixes or save your own project presets (stored in your browser).
m²
Total surface receiving mortar or plaster.
m
m
mm
mm
mm
Bed or joint average thickness.
:
Examples: 1:4 plaster, 1:5 mortar, etc.
×
Converts wet volume to dry ingredient volume.
%
Increase for moist sand volume swell.
%
kg/m³
Pick from supplier profiles below or enter manually.
kg/bag
Example Data

A few common scenarios for quick reference:

Mode Area Thickness Ratio (C:S) Bulking Wastage Resulting Sand (m³)
Plaster 50 m² 12 mm 1:4 20% 5%
Plaster 80 m² 20 mm (two coats) 1:5 15% 7%
Mortar 30 m² 10 mm 1:5 20% 5%
Results
Wet volume 0.000 m³
Dry volume 0.000 m³
Sand fraction 0.000
Sand volume (before bulking) 0.000 m³
Sand volume with bulking 0.000 m³
Sand volume incl. wastage 0.000 m³
Sand weight 0.00 kg
Bag count 0
Coat-by-Coat Coverage Chart
Visualize contribution per coat or layer for selected metric.
Supplier Density Profiles
kg/m³
Profiles save in your browser. Stored internally in kg/m³.
Formula Used

Core calculations:

  • Area (A) from input or L × H.
  • Thickness (t) converted to meters (or feet) as needed.
  • Wet volume: Vw = A × t.
  • Dry volume: Vd = Vw × k where k is the dry factor.
  • Sand fraction for ratio C:S = c:s: f = s / (c + s).
  • Sand volume (dry): Vs = Vd × f.
  • Bulking: Vb = Vs × (1 + B), where B is bulking (decimal).
  • Wastage: Vf = Vb × (1 + W), where W is wastage (decimal).
  • Weight: m = ρ × Vf, where ρ is sand density.
  • Bags: n = m / mbag (rounded up).

Defaults: dry factor 1.33, bulking 20%, wastage 5%, density 1600 kg/m³ (≈ 100 lb/ft³).

How to Use
  1. Choose units and mode; load a preset if desired.
  2. Enter area directly, or provide length and height to compute area.
  3. For plaster, select coats and set each coat thickness.
  4. Set the mix ratio, dry factor, bulking, wastage, bag size, and density.
  5. Pick a supplier profile to auto-fill density, or add your own.
  6. Click Calculate; review results and the coat-by-coat chart.
  7. Use Download CSV or Download PDF to export results.
FAQs

A common value is 1.33 to account for voids and swell when converting wet volume to dry ingredients. Adjust if your local practice differs.

Moist fine sand may bulk 15–30%. Perform a field bulking test or consult supplier data to refine the percentage.

Yes. The mix ratio sets the sand fraction of the dry volume. Higher sand parts increase the sand volume proportionally.

Use your supplier’s dry bulk density. Typical dry sand is ~1600 kg/m³ (about 100 lb/ft³), but it varies with grading and moisture.

Yes, you can enter decimal parts for cement and sand to match specialty specifications.

Bag counts are estimates based on density and chosen bag size, then rounded up. Always verify against supplier packaging and on-site conditions.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.