About the Aggregate Calculator
Coarse aggregate for concrete or a sub-base, by volume, weight and bulk bag count.
Also known as: ballast calculator, coarse aggregate quantity, stone for concrete, sub base calculator.
How to use this calculator
- Enter calculate for, bulk density and the other fields.
- The result updates instantly as you type — press Calculate (or Enter) at any time.
- Review the breakdown shown under the main result.
- Use Copy result or Share to save the answer or send a link with your inputs.
Formula
aggregate volume = dry volume × aggregate parts ÷ total parts
Worked example
Using the values pre-filled in the calculator above:
- Calculate for: A concrete mix
- Concrete volume = 2 m³
- Mix ratio: 1 : 1.5 : 3 (M20) — 20 MPa — slabs and footings
- Bulk density = 1,500 kg/m³
the calculator returns:
- Aggregate required: 1.68 m³
- In tonnes: 2.52
- Bulk bags (850 kg): 3
- In kilograms: 2,520