Hindustan RMC Calculator: Concrete Volume, Trucks & Cost
This Hindustan RMC calculator works out how much ready-mix concrete to order: RMC volume in cubic metres for a slab, footing, column or beam, how many transit-mixer trucks that means, and the total RMC cost with GST and pumping charges if a plant rate is entered. It also explains which RMC grade suits each part of a house.
By Umer Sattar Updated 21 Oct 2026
M20 · 3.6 m³ net (127 CFT)
Order 3.74 m³ · 1 truck
- Net volume
- 3.6 m³
- With extra
- 3.74 m³
- Cement (site mix)
- 29 bags
- Trucks
- 1
Site-mix equivalent for M20 (1 : 1.5 : 3): sand 1.51 m³, aggregate 3.02 m³. RMC plants batch by weight, so this is for comparison only.
How to calculate RMC volume
Concrete is ordered by volume, so every RMC order starts with length × width × thickness. A slab of 6 m × 4 m at 150 mm thick is 6 × 4 × 0.15 = 3.6 m³. Site engineers then add 3–5% for uneven shuttering, spillage and the concrete left in the pump line, so this slab is booked as about 3.75 m³.
RMC volume (m³) = Length × Width × Thickness × Number Order volume = RMC volume × 1.03 to 1.05 Trucks = Order volume ÷ transit mixer size (round up) Volume in feet : ft³ ÷ 35.315 = m³
How many RMC trucks are needed for 100 m³ of concrete?
With the common 6 m³ transit mixers, 100 m³ needs 17 trips; with 7 m³ mixers, 15. Plants plan the gap between trucks so the pour never stops, so share the total volume with them a day before.
RMC grade reference chart
| Grade | Strength (28 days) | Typical use in houses | Nominal mix |
|---|---|---|---|
| M10 | 10 N/mm² | PCC below footings, levelling | 1 : 3 : 6 |
| M15 | 15 N/mm² | PCC flooring, light non-structural work | 1 : 2 : 4 |
| M20 | 20 N/mm² | RCC slabs, beams and footings in mild exposure | 1 : 1.5 : 3 |
| M25 | 25 N/mm² | Columns, slabs in moderate exposure, multi-storey | Design mix |
| M30 | 30 N/mm² | Heavy loads, coastal and severe exposure | Design mix |
IS 456 allows M20 for reinforced concrete only in *mild* exposure. For *moderate* exposure (concrete protected from heavy rain but in a humid climate, or buried in non-aggressive soil) the minimum is M25, and coastal towns like Mumbai, Chennai or Kochi usually need higher grades still. That is why many engineers now specify M25 as the default for columns even in houses.
M25 and above are design mixes: the RMC plant proportions cement, sand, aggregate and admixture by weight after trials (IS 10262). Ask for the mix design sheet and the cube test results, which is one of the main advantages of RMC over site mixing.
RMC mix design and material quantities
For the nominal grades (M10, M15, M20), the calculator also shows the mix design quantities a site would need to mix the same concrete by hand: dry volume is taken as 1.54 times the wet volume, split in the mix ratio, with cement at 1,440 kg/m³ and 50 kg bags. Plants batch by weight, so this is a comparison, not the plant's recipe.
What is the water-cement ratio for M20 concrete?
IS 456 sets a maximum water-cement ratio of 0.55 for RCC in mild exposure and 0.50 in moderate exposure. RMC plants typically work around 0.45–0.50 for M20 using admixtures for workability.
RMC cost estimator: GST and pumping charges
Plant rates are usually quoted per cubic metre, before GST. Ready-mix concrete attracts 18% GST, and a boom or line pump is charged separately, often as a fixed charge per pour plus extra above a minimum quantity. Enter the plant rate and the pump charge, and the calculator adds GST to give a realistic total.
- Ask whether the rate includes the pump; many quotes don't.
- Check the minimum order: small pours (under about 3–4 m³) may be charged as a part-load.
- Confirm the waiting-time charge: if the site isn't ready, trucks charge for waiting.
RMC or site-mix concrete?
In cities, RMC has become the default for slabs because it is consistent, fast and backed by cube tests. Site mixing still makes sense for very small pours or remote sites without a plant within an hour's travel, since concrete must be placed before it begins to set. Whichever is used, curing for at least 7 days (10 for blended cements) matters as much as the grade.
Note: this tool is independent and not connected with any company named Hindustan or with any RMC plant.
RMC Calculator: questions people ask
How do I calculate RMC volume for a slab?
Multiply length × width × thickness in metres. A 6 m × 4 m slab at 0.15 m thick is 3.6 m³; order about 3.7–3.8 m³ to allow for spillage.
Which RMC grade is best for house construction?
M20 for slabs and footings in mild exposure, and M25 for columns or for humid and coastal areas. Follow your structural engineer's drawing.
How many RMC trucks are needed for 100 m³?
About 17 trips with 6 m³ transit mixers or 15 with 7 m³ mixers.
What is the GST on RMC?
Ready-mix concrete is charged 18% GST. Pumping is usually billed separately.
What is the difference between RMC and site-mix concrete?
RMC is batched by weight at a plant with quality control and cube testing; site mix is proportioned by volume on site. RMC is more consistent, especially for M25 and above.
How many cement bags are in 1 m³ of M20 concrete?
For a nominal 1 : 1.5 : 3 mix, about 8 bags (50 kg) per cubic metre. RMC design mixes may use less cement plus fly ash or admixtures.