First Principles Volume Calculator • Measurement Book Style
This tool provides estimates based on general algorithms. It does NOT constitute professional engineering advice. Structures must be verified by a licensed engineer per IS Codes. By using this tool, you agree to indemnify K-First against any financial losses.
No deductions added
| Grade | Ratio | Use Case |
|---|---|---|
| M10 | 1:3: 6 | Lean concrete, non-structural use (PCC work) |
| M15 | 1:2: 4 | Standard grade for minor structural work |
| M20 | 1:1.5: 3 | Most common for residential RCC (beams, slabs, columns) |
| M25 | 1:1: 2 | High strength for commercial/industrial structures |
Wet Volume × 1.54 Convert wet concrete volume to dry material volume. The 1.54 coefficient accounts for air voids that close during compaction.
Wet Volume
= Finished concrete volume (L × W × H), 1.54
= Dry volume coefficient for concrete Dry Volume × (Cement Ratio / Sum of Ratios) Calculate cement volume from dry volume and mix ratio.
Dry Volume
= Total dry material volume, Cement Ratio
= 1 (in all standard mixes), Sum of Ratios
= e.g., 1+1.5+3 = 5.5 for M20 Cement Volume (cft) ÷ 1.226 Convert cement volume to 50kg bags. One bag = 1.226 cft.
1.226 cft
= Volume of one 50kg cement bag (Wall Volume - Opening Volume) ÷ Brick Unit Volume Net wall volume divided by brick + mortar volume.
Wall Volume
= L × H × T of wall, Opening Volume
= Windows + Doors deducted, Brick Unit Volume
= (Brick L + 10mm) × (Brick H + 10mm) × (Brick W) Standard M20 mix (1:1.5:3) for a residential slab
Calculate dry volume
1 m³ × 1.54 = 1.54 m³ dry volume Sum of ratio parts (M20 = 1:1.5:3)
1 + 1.5 + 3 = 5.5 parts Calculate cement volume
1.54 × (1/5.5) = 0.28 m³ = 8.08 bags Calculate sand volume
1.54 × (1.5/5.5) = 0.42 m³ = 14.83 cft Calculate aggregate volume
1.54 × (3/5.5) = 0.84 m³ = 29.66 cft Result: 8 bags cement, 15 cft sand, 30 cft aggregate
9-inch wall (228mm) with standard Kerala bricks 230×110×75mm
Calculate wall volume
10 sq.m × 0.228m thick = 2.28 m³ Calculate brick + mortar unit volume
(230+10) × (110) × (75+10) × 10⁻⁹ = 0.00224 m³ Calculate number of bricks
2.28 ÷ 0.00224 = 1018 bricks Result: 1018 bricks (approx 1020 for ordering)
In Kerala, M-Sand (manufactured sand) is commonly used instead of river sand. Material ratios remain the same, but M-Sand may require slightly more water.
Default 5% wastage is conservative. Site conditions may require 8-10% for complex formwork or remote locations.
Kerala standard brick: 230×110×75mm. Other states may use 230×115×75mm. Verify local brick dimensions.