What is the Plaster Calculator?
A plaster calculator estimates the cement and sand needed to plaster a wall of given area and thickness, using a chosen mix ratio (commonly 1:4 or 1:6).
Formula
Wet volume = Area × thickness · Dry volume = Wet × 1.27 (plaster bulking)
- 1.27 — Dry volume factor for plaster (vs 1.54 for concrete)
Step-by-step example
Setup: 100 m² wall, 12 mm plaster, 1:6 mix.
- Wet vol = 100 × 0.012 = 1.2 m³
- Dry vol = 1.524 m³
- Cement = 1.524 / 7 = 0.218 m³ ≈ 6.3 bags
- Sand = 1.524 × 6/7 ≈ 1.31 m³
Answer: ≈ 6.3 bags cement + 1.31 m³ sand
Frequently asked questions
1:4 or 1:6?
1:4 for external walls and ceilings, 1:6 for internal walls. 1:3 for waterproofing layers.