Plaster Calculator
Find the cement bags and sand needed for wall or ceiling plaster. Choose thickness and mix ratio, enter the area or the room size, and get the result instantly.
1. Area to plaster
2. Plaster details
Method: wet volume = area × thickness, plus joints & wastage, × 1.27 dry volume factor. Cement density 1,440 kg/m³, 50 kg bag. 1 m³ = 35.315 cft.
Quick reference: material per 100 m² of plaster
| Thickness | Mix | Cement (bags) | Sand (cft) |
|---|---|---|---|
| 6 mm (ceiling) | 1:3 | 6.6 | 24.2 |
| 12 mm | 1:6 | 7.5 | 55.4 |
| 12 mm | 1:4 | 10.5 | 51.7 |
| 15 mm | 1:6 | 9.4 | 69.2 |
| 20 mm (external) | 1:4 | 17.6 | 86.1 |
Need the full method, IS 1200 deduction rules and site tips to stop plaster cracks? Read our plaster calculation guide. For brick walls, see bricks, cement and sand for brickwork, or browse all civil engineering calculators.
FAQ
How many bags of cement are needed for 100 sq ft of plaster?
For 12 mm plaster in 1:6, about 0.7 bag per 100 sq ft (9.29 m²). In 1:4 it is about 1 bag.
Why is 1.27 used?
Dry cement and sand lose volume when mixed with water, because fine particles fill the gaps. About 1.27 times the wet volume of dry material is needed.