Regional mix designChoose your project worksheetChoose
CONCRETE RATIO TOOLS
50 kg cement-bag concrete calculator
Find sand, aggregate, mixer water and designed concrete volume for your cement supply by scaling a material-specific concrete mix.
Your cement supply
Fractions represent weighed portions of a bag.
Scales the cement component of the selected design. Fly ash, GGBS and other additions remain separate ingredients.
Start with a different mix →SCALED M30 BATCH
| Material | Your batch · kg |
|---|---|
| Cement | 50 |
| Fine aggregate (as batched) | 91.15 |
| Coarse aggregate (as batched) | 164.68 |
| Water to add at mixer | 21 |
| Chemical admixture | 0.5 |
50 ÷ 375.5429 = 0.1331 m³Aggregate weights and mixer water include the transferred moisture assumptions. This is calculated volume, not a measured yield.
Using the illustrative M30 example. You can send your own mix from the main calculator.
One bag does not have one universal concrete yield
A mix containing 400 kg of cement per designed cubic metre scales to 0.125 m³ per 50 kg of cement. A different cement content gives a different answer. This tool uses the selected mix’s cement content and scales every other ingredient by the same factor.
How to calculate cement bags per cubic metre
For 50 kg bags, bag consumption = designed concrete volume × cement content per m³ ÷ 50. For example, 2 m³ at 400 kg cement per m³ uses 800 kg, or 16 bags. The inverse calculation is concrete volume = available cement mass ÷ cement content per m³, which is what the calculator above uses.
A fractional bag result describes material consumption. Round up only for a separate whole-bag purchase estimate; do not add the entire rounded purchase mass to the same batch. These are cement bags, not bags of premixed concrete containing aggregate.
Cement and total binder are different
When a design includes supplementary materials, the bag count refers to the base cement component. The required fly ash, GGBS or silica fume is still shown separately. Dividing by total binder instead of cement would underestimate the batch represented by the available cement.
Use Scale by cement bags from the main lab to transfer your material assumptions. Review the worksheet, measure actual masses and test the trial; theoretical scaling does not establish workability or strength.