Concrete Material Calculator
This concrete material calculator breaks a pour into its ingredients: cement (50 kg bags), sand, gravel/aggregate — and the combined ballast figure UK buyers order. Use it to batch your own mix or to sanity-check a ready mix quote.
How to Use This Calculator
- Enter your dimensions — feet for lengths, inches for thickness.
- Adjust the options — waste percentage, bag size and your local concrete price.
- Read your results — volume, bags, weight and cost update live as you type.
The Formula
Dry volume = wet volume × 1.54, split by mix ratio parts; ballast = sand + aggregate combined Worked example: 1 m³ at 1:2:3 → 0.257 m³ cement (≈ 8 bags), 0.513 m³ sand, 0.77 m³ gravel — or 1.28 m³ of all-in ballast plus cement.
The concrete calculator aggregate and concrete calculator gravel outputs matter because coarse aggregate is the bulk of every mix — roughly half the finished volume. Sand fills the voids between stones; cement paste glues it together.
As a ready mix calculator: compare the delivered price against your batching cost (cement bags + sand + gravel + your time). The truck usually wins above one cubic meter — and always wins on consistency.
As a dry pour calculator: dry-pour projects (placing bagged mix dry and misting) still need the same total volume — calculate it with the bag calculator, and reserve dry pour for non-structural pads and paths where lower, less-uniform strength is acceptable.
Frequently Asked Questions
Common questions about the concrete material calculator.
How much cement, sand and gravel per m³ of concrete?
At 1:2:3, about 8 × 50 kg cement bags, 0.51 m³ sand and 0.77 m³ gravel per finished cubic meter (dry factor 1.54 included).
What is ballast?
Pre-blended sand and gravel (all-in aggregate), common in the UK. The calculator's ballast line combines the sand and aggregate volumes — add cement per the ratio.
Ready mix or self-batching — which is cheaper?
Self-batching saves money only on small pours. Above ~1 m³ (1.3 yd³), ready mix is usually cheaper once your time and consistency risk are counted.
Is dry pour concrete as strong?
No — dry-poured slabs hydrate unevenly and test weaker than mixed concrete. Fine for garden paths and pads; avoid for driveways and structural work.
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