Plaster quantity calculator
Plaster mortar volume = area × plaster thickness. From the volume the calculator gives the cement at 300 kg per m³ of mortar divided by 50 kg per bag, and the sand at 1.1 m³ per m³ of mortar.
Calculator
- Cement
- 60 bags
- Sand
- 11 m³
- Mortar volume
- 10 m³
Method, step by step
- Multiply the plaster area in m² by the thickness in metres (2 cm = 0.02 m) to get the mortar volume.
- Multiply the mortar volume by the cement ratio in kg, divide by the bag weight and round up.
- Multiply the mortar volume by the sand ratio for the sand in m³.
Worked example
Inputs
- Plaster area (m²): 500
- Plaster thickness (m): 0.02
- Mortar volume = area × thickness = 500 × 0.02 = 10 m³.
- Cement = 10 × 300 ÷ 50 = 60 bags (rounded up).
- Sand = 10 × 1.1 = 11 m³.
Result
- Cement
- 60 bags
- Sand
- 11 m³
- Mortar volume
- 10 m³
Assumptions and default ratios
| Ratio | Default value |
|---|---|
| Cement in plaster mortar | 300 kg/m³ |
| Cement bag weight | 50 kg/bag |
| Sand in plaster mortar | 1.1 m³ per m³ of mortar |
- The cement and sand ratios are editable defaults; follow the mix approved for your project.
- The thickness is a constant average. The spatter coat, screeds and waste are not included.
Frequently asked questions
How much cement does one square metre of plaster need?
At 2 cm one square metre is 0.02 m³ of mortar; at 300 kg per m³ that is about 6 kg of cement. Enter the whole area, since bags are rounded up on the total.
What thickness should I enter?
The average plaster thickness in metres from the specification or as actually applied, e.g. 0.02 for 2 cm.
Does it work for ceilings?
Yes. Add the ceiling area to the walls, or calculate it separately if the thickness differs.
Add the result to your project BOQ in Ta3mir
In Ta3mir the same calculators work inside your project: send a result to a BOQ line in one click and save your own default ratios for every calculation.