Construction & estimating · Site operations
Concrete mix design (ACI 211.1) calculator
Batch quantities per m³ (water, cement, coarse and fine aggregate) by the ACI absolute-volume method.
Standard: ACI 211.1 absolute volume, non-air-entrained (simplified)
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Inputs in the worked example
The live calculator starts with these values; change any of them and every result, check and diagram updates instantly.
| Input | Value | Unit |
|---|---|---|
| Specified strength | 32 | MPa |
| Standard deviation (0 if unknown) | 4 | MPa |
| Slump | 80 | mm |
| Maximum aggregate size | 20 | mm |
| Sand fineness modulus | 2.7 | |
| CA dry-rodded density | 1600 | kg/m³ |
| Cement SG | 3.15 | |
| CA SG | 2.68 | |
| FA SG | 2.64 | |
| Max w/c (durability) | 0.5 | |
| Min cement | 320 | kg/m³ |
Worked example — results
| Result | Value | Unit |
|---|---|---|
| Target strength f′cr | 37.8 | MPa |
| w/c | 0.442 | |
| Water | 200 | kg/m³ |
| Cement | 453 | kg/m³ |
| Coarse aggregate | 1,008 | kg/m³ |
| Fine aggregate | 687 | kg/m³ |
| Entrapped air | 2.0 | % |
| Fresh density | 2,348 | kg/m³ |
- ✓ w/c ≤ durability limit
Method, formulas and assumptions
- f′cr = max(f′c + 1.34s, f′c + 2.33s − 3.5); +8.3 MPa if s unknown
- w/c from ACI table (interpolated); water from slump and aggregate size
- Fine aggregate by absolute volume. Trial batches are required. Australian practice uses AS 1379 and supplier mixes.
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For preliminary design and education. Check every result against the current standard and your own engineering judgement before use.