Plaster Calculator
Calculate the plaster volume and cement/sand quantities needed for a wall coat.
- Free to use
- Accurate results
- No registration required
- Works on all devices
Enter your wall dimensions and plaster thickness to find the plaster volume and cement/sand quantities needed.
12-15mm is typical for internal wall plaster; external plaster is often 15-20mm.
Your result
0.18
Plaster volume
Cement bags (50kg)1.4
Sand volume0.201
AI explanation
Formula
Plaster volume = length × height × thickness; dry volume = plaster volume × (1 + wastage%) × 1.33; cement/sand split by mix ratioWorked example
5m × 3m wall, 12mm plaster, 1:4 mix, 5% wastage
| Field | Value |
|---|---|
| Wall length (m) | 5 |
| Wall height (m) | 3 |
| Plaster thickness (mm) | 12 |
| Plaster mix | 1:4 (cement:sand) |
| Wastage allowance (%) | 5 |
| Plaster volume | 0.18 |
| Cement bags (50kg) | 1.4 |
| Sand volume | 0.2011 |
Assumptions
- Assumes a single coat of the given thickness — a two-coat plaster job needs this calculation run twice (once per coat) or the total combined thickness entered.
- Mortar dry-volume factor of 1.33 is used, since plaster (like mortar) has no coarse aggregate.
Frequently asked questions
How thick should wall plaster be?
12-15mm is typical for internal walls; external walls are often plastered 15-20mm thick for extra weather protection — check your project's specification.
Should I calculate both coats together or separately?
Either works — enter the combined thickness of both coats for a single total, or run this calculator twice with each coat's individual thickness.
What plaster mix ratio is typical?
1:4 or 1:6 (cement:sand) is common for general internal plaster; 1:3 is used for external or higher-strength plaster work.