Concrete Mix Calculator: Cement, Sand and Aggregate
Enter the volume of concrete and the mix by volume (cement : sand : aggregate). See how many bags of cement and how much sand and aggregate to order for a site-batched nominal mix.
- Cement (bags)
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- Cement bags to buy (rounded up)
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- Cement
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- Sand
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- Aggregate
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- Sand
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- Aggregate
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- Dry volume of materials
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Assumptions
- The parts are by loose volume, as in site batching with boxes or buckets.
- Dry volume = wet volume × the dry volume factor you enter; it covers voids and bulking.
- Cement volume is turned into mass with the bulk density you enter, then into bags.
- No allowance for waste or spillage is added. Water is not included.
Estimate Checked 28 October 2026 IS 456:2000 Plain and Reinforced Concrete, Code of Practice: clause 9.3 and Table 9 (nominal mixes, by mass), clause 10.2.4 (volume batching) All sources
How it is calculated
- Dry volume = concrete volume × dry volume factor
- Cement volume = dry volume × cement parts ÷ (cement + sand + aggregate parts); sand and aggregate the same way
- Cement mass = cement volume × cement bulk density
- Cement bags = cement mass ÷ bag size (a 94 lb bag = 42.64 kg)
- IS 456:2000 Table 9 sets nominal mixes (M20 or lower) by mass instead, as kg of aggregate per 50 kg of cement, and clause 10.2.4 allows volume batching only where weighing is not practical and bulk densities are known.
Worked example
One cubic metre of a 1 : 2 : 4 mix with 50 kg bags.
| You enter | |
|---|---|
| Concrete volume (wet, in place) | 1 |
| Volume unit | Cubic metres (m³) |
| Mix by volume (cement : sand : aggregate) | 1 : 2 : 4 |
| Cement parts | 1 |
| Sand parts | 2 |
| Aggregate parts | 4 |
| Dry volume factor (common practice 1.54) | 1.54 |
| Cement bulk density | 1,440 kg/m³ |
| Cement bag size | 50 kg |
| You get | |
| Cement (bags) | 6.34 |
| Cement bags to buy (rounded up) | 7 |
| Cement | 316.8 kg |
| Sand | 0.44 m³ |
| Aggregate | 0.88 m³ |
| Sand | 15.54 ft³ |
| Aggregate | 31.08 ft³ |
| Dry volume of materials | 1.54 m³ |
For this concrete, order about 7 bags of cement (316.8 kg), 0.44 m³ of sand and 0.88 m³ of aggregate, before any allowance for waste.
Questions
Why multiply by 1.54?
Loose cement, sand and aggregate have air between the grains, and the finished concrete fills those gaps. So you need more loose material than the volume you pour. Site practice often uses 1.54; it is an adjustable figure, not one set by a standard.
Which mix should I use?
That is a design decision for your engineer or your building code. Lean mixes such as 1 : 4 : 8 are usually for blinding and fill, richer mixes for structural work. This tool only turns the mix you choose into quantities.
Sources and checks
- IS 456:2000 Plain and Reinforced Concrete, Code of Practice: clause 9.3 and Table 9 (nominal mixes, by mass), clause 10.2.4 (volume batching)
- IS 875 (Part 1):1987 Dead loads, Table 1: cement, ordinary, 1,440 kg/m³
- US Army FM 5-428 Concrete and Masonry (1998): para 1-16 (94 lb sack = 1 loose cubic foot) and the 1:2:3 site mix
- NIST SP 811 (2008), Appendix B: cubic foot, cubic yard and pound conversion factors
Last checked: 28 October 2026. This tool passes 7 automatic tests before every release. How we check our tools
Your numbers never leave your device: the calculation runs in your browser and nothing you type is sent or stored.
This is an estimate for ordering materials. Real quantities depend on your sand, aggregate, moisture and site practice, and on any mix design your engineer specifies. Results are estimates for planning and learning. They are not a design check and do not replace a qualified engineer or your local building/electrical code.