🏗️ Structural · 5 min read
Cement, Sand, and Gravel Quantities per Cubic Meter of Concrete
This is the single most-used concrete estimating calculation. It rests on one idea: dry loose materials occupy about 1.5 times the volume of the finished concrete.
The dry-volume factor
When water is added, cement paste fills the voids between aggregate and the mix consolidates. To get 1 m³ of compacted concrete you must batch about 1.54 m³ of dry loose materials (1.52–1.57 depending on grading).
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Split by the ratio
Sum of ratio parts = C + S + G
Cement volume = 1.54 × C / (C+S+G)
Cement bags = cement volume / 0.0347 (one 40 kg bag ≈ 0.0347 m³)
Sand = 1.54 × S / (C+S+G) | Gravel = 1.54 × G / (C+S+G)
Cement volume = 1.54 × C / (C+S+G)
Cement bags = cement volume / 0.0347 (one 40 kg bag ≈ 0.0347 m³)
Sand = 1.54 × S / (C+S+G) | Gravel = 1.54 × G / (C+S+G)
Ready reference (per m³, before wastage)
| Mix | Cement (40 kg bags) | Sand (m³) | Gravel (m³) |
|---|---|---|---|
| 1:3:6 | 4.5 | 0.47 | 0.94 |
| 1:2:4 | 6.3 | 0.44 | 0.88 |
| 1:1.5:3 | 8.0 | 0.42 | 0.84 |
| 1:1:2 | 11.5 | 0.40 | 0.80 |
Add wastage and round to delivery units
- Cement: add 3–5% and round up to whole bags.
- Sand and gravel: add 5–10% for handling loss and bulking variation; order in whole cubic-metre or per-truckload increments.
- Water: ~20–25 L per bag of cement for a workable mix (w/c ≈ 0.5–0.6), reduced if a plasticiser is used.
🏗️ Using EngEst Pro
EngEst Pro applies the 1.54 factor and your mix ratio to every concrete volume you enter, adds wastage, and outputs Portland cement bags, sand, and gravel as priced BOM lines in your local currency.
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