What is the standard thickness for wall plastering in India?

Internal walls typically use 12mm thickness plaster. External walls use 20mm thickness. Ceiling plaster is usually 6mm thick.

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Plastering Calculator

Cement & Sand for Wall Plastering

Surface Type

Length (m)

Height / Width (m)

Plaster Thickness

Mix Ratio

Number of Coats

Cement Required

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Plastering Calculator – Cement and Sand for Wall Plastering India

Our plastering calculator helps civil engineers, contractors, and builders calculate the exact quantity of cement bags and sand needed for wall plastering. Covers internal, external, and ceiling plaster with all standard mix ratios used in India.

Uses the standard dry volume factor of 1.35 for plastering work and cement density of 1440 kg/m³.

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Plastering Calculation Formula

Volume of Plaster = Area × Thickness
Dry Volume = Wet Volume × 1.35
Cement = Dry Volume × (1/Sum of Ratios) × 1440 / 50
Sand = Dry Volume × (Ratio of Sand / Sum of Ratios)

Example – 10m × 3m Wall, 12mm, 1:4 Mix

Area = 10 × 3 = 30 m²
Wet Volume = 30 × 0.012 = 0.36 m³
Dry Volume = 0.36 × 1.35 = 0.486 m³
Cement = 0.486 × (1/5) × 1440 / 50 = 2.8 bags
Sand = 0.486 × (4/5) = 0.39 m³

Standard Plaster Thickness in India

Ceiling Plaster

6mm

Internal Wall

12mm

External Wall

20mm

Waterproof

12–15mm

Cement Bags per 100 sq ft (Quick Reference)

6mm, 1:3 mix

1.2 bags

12mm, 1:4 mix

2.5 bags

20mm, 1:6 mix

2.8 bags

12mm, 1:6 mix

1.7 bags

Frequently Asked Questions

For 100 sq ft (9.29 m²) wall plastering at 12mm thickness with 1:4 mix: approximately 2.5 bags of cement (50kg each) and 0.27 m³ of sand. Use our calculator for exact results based on your dimensions.

1:4 (cement:sand) is the standard mix for internal wall plastering in India. For external walls, 1:5 or 1:6 is used. For waterproof plastering, 1:3 with waterproofing compound is recommended.

The dry volume factor for plastering is 1.35 (compared to 1.54 for concrete). This means the dry mix quantity should be 1.35 times the wet plaster volume to account for voids in dry materials.

For a standard 12×10 ft room (4 walls, 10 ft height) at 12mm thickness with 1:4 mix: approximately 15–18 bags of cement. Use our calculator with your exact room dimensions for accurate results.