RCC Material & Ready Mix Concrete (RMC) Calculator
Estimate required bags of Cement, Sand (cft/tons), Aggregate (cft/tons), Water, and total cost for concrete slabs.
Residential slabs, beams and columns
Conventionally 1.54 to allow for voids and bulking.
How this is calculated
Mix ratio for M20 is 1 : 1.5 : 3 (cement : sand : aggregate), summing to 5.5 parts.
Dry volume = 10.00 × 1.54 = 15.400 m³
Cement = 15.400 × 1/5.5 × 1440 kg/m³ ÷ 50 = 80.64 bags
Changing the grade changes the ratio used throughout, so M15 and M25 give genuinely different quantities.
RCC Material & Ready Mix Concrete (RMC) Calculator: how it works
Concrete quantities follow from the mix ratio and the dry volume factor. Changing the grade genuinely changes every quantity.
Dry volume first
Dry ingredients occupy more space than the finished concrete, because water fills the voids between particles during mixing. The conventional factor is 1.54.
Dry volume = Wet volume × 1.54
Nominal mix ratios
| Grade | Cement : Sand : Aggregate | Sum | Typical use |
|---|---|---|---|
| M10 | 1 : 3 : 6 | 10 | Foundation levelling (PCC) |
| M15 | 1 : 2 : 4 | 7 | Light pavements, boundary walls |
| M20 | 1 : 1.5 : 3 | 5.5 | Residential slabs, beams, columns |
| M25 | 1 : 1 : 2 | 4 | RCC columns, heavier work |
Cement bags = (Dry volume × cement part ÷ sum) × 1440 ÷ 50
- 1440 kg/m³ is the density of cement
- 50 kg per bag
Worked example
Worked example · 10 m³ of M20 concrete
Given
- Wet volume: 10 m³
- M20 mix 1:1.5:3, sum 5.5
Working
- 1Dry volume = 10 × 1.54 = 15.4 m³
- 2Cement volume = 15.4 × 1 ÷ 5.5 = 2.8 m³
- 3Cement = 2.8 × 1440 ÷ 50 = 80.6 bags
- 4Sand = 15.4 × 1.5 ÷ 5.5 = 4.2 m³ = 148.3 cft
- 5Aggregate = 15.4 × 3 ÷ 5.5 = 8.4 m³ = 296.6 cft
81 bags of cement, 148 cft sand, 297 cft aggregate
Grade matters
The same 10 m³ needs 44 bags at M10, 63 at M15, 81 at M20 and 111 at M25. Any calculator that gives the same answer regardless of the grade you select is applying one ratio and ignoring your choice.
Based on
- IS 456: Plain and Reinforced Concrete — Code of Practice
Frequently asked questions
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