Estimate cement, sand, aggregate and water for a concrete mix from the wet concrete volume you enter. Set your own cement:sand:aggregate ratio, dry-volume factor, waste allowance, cement bag weight, bulk density and water-cement ratio, then review material quantities and an optional material-only cost.
All numeric fields are blank. The faded zero is only a placeholder, so the number you type replaces it instead of being added after it.
Use the mix ratio, dry-volume factor, cement density and water-cement ratio required by your chosen estimating method or project specification. This calculator does not choose a structural mix design.
Your result will appear after you press Calculate Mix Materials.
The dry material volume is divided by the total ratio parts, then each material receives its share.
The tool separates wet volume, dry volume, cement, sand, aggregate, water and material cost so every assumption stays visible.
Estimate cement volume, mass and whole bags from your inputs.
Estimate sand volume from the selected mix ratio.
Estimate coarse aggregate volume from the selected ratio.
Estimate water litres from your entered water-cement ratio.
Apply your own dry-volume conversion factor.
Estimate cement, sand and aggregate material cost.
A Cement Mixing Calculator estimates the material quantities needed for a chosen concrete mix ratio. The calculator does not decide the correct mix. Instead, it takes the wet concrete volume, dry-volume factor, cement:sand:aggregate ratio, cement bulk density and water-cement ratio that you enter and applies the arithmetic consistently.
The finished concrete volume is the space the concrete will occupy after mixing and placing. If you already know that volume, enter it directly. If you only know slab dimensions, use the slab mode and enter length, width and thickness.
Wet Volume (m³) = Length (m) × Width (m) × [Depth (mm) ÷ 1000]The calculator applies your selected waste percentage to wet volume before converting to dry materials. This keeps the contingency visible and avoids hiding extra material inside the ratio inputs.
Dry ingredients occupy a different loose volume from compacted finished concrete. Estimating methods often use a multiplier to convert wet concrete volume into an approximate dry-material volume. Because the exact planning factor can vary by method, material grading and assumptions, this calculator leaves the value editable rather than forcing a fixed number.
Dry Volume = Wet Volume With Waste × Entered Dry-Volume FactorA ratio such as 1:2:4 contains seven total parts. Cement represents one part, sand two parts and aggregate four parts. The calculator works with any positive ratio values you enter.
Total Parts = Cement Part + Sand Part + Aggregate Part| Example Ratio | Total Parts | Cement Share | Sand Share | Aggregate Share |
|---|---|---|---|---|
| 1 : 1 : 2 | 4 | 25.0% | 25.0% | 50.0% |
| 1 : 1.5 : 3 | 5.5 | 18.2% | 27.3% | 54.5% |
| 1 : 2 : 4 | 7 | 14.3% | 28.6% | 57.1% |
| 1 : 3 : 6 | 10 | 10.0% | 30.0% | 60.0% |
Cement Volume = Dry Volume × Cement Part ÷ Total PartsSand Volume = Dry Volume × Sand Part ÷ Total PartsAggregate Volume = Dry Volume × Aggregate Part ÷ Total PartsCement is often bought by mass, but the ratio calculation produces a volume share. Enter the bulk density used by your estimating method so the calculator can convert cement volume into kilograms.
Cement Mass (kg) = Cement Volume (m³) × Entered Cement Bulk Density (kg/m³)Enter the cement bag weight you plan to buy. The calculator divides estimated cement mass by bag weight and rounds up to whole bags.
Whole Bags = Cement Mass ÷ Bag Weight, Rounded UpA water-cement ratio is normally expressed by mass. If you enter a value of 0.50, the calculator multiplies cement mass by 0.50 and treats one kilogram of water as approximately one litre for the planning display.
Water (L) ≈ Cement Mass (kg) × Entered Water-Cement RatioThe calculator does not tell you what water-cement ratio to use. Workability, strength, durability, aggregate moisture, admixtures and project specifications can all affect water demand and mix design.
Suppose you need 1.00 m³ of finished concrete and choose a dry-volume factor of 1.50 with a 1:2:4 ratio. The dry volume becomes 1.50 m³ before waste adjustments. The seven total ratio parts divide that dry volume into approximately 0.214 m³ cement, 0.429 m³ sand and 0.857 m³ aggregate. Cement mass and bags then depend on the bulk density and bag weight you enter.
Every numeric field is actually empty. The light zero is only a placeholder. If you type 1.5, the stored value is 1.5 — not 01.5. Reset clears the inputs and shows the placeholder again.
The calculator adds cement bag cost, sand cost and aggregate cost. It does not include labour, delivery, mixer hire, formwork, reinforcement or finishing.
Total Material Cost = Cement Bag Cost + Sand Cost + Aggregate CostSite mixing is often used for small slabs, repairs, post holes, footings and other projects where ready-mix delivery is not practical. The arithmetic can be simple, but the quality of the finished concrete still depends on consistent batching, appropriate materials, correct water control and a mix suitable for the project.
Traditional ratio notation is often expressed by volume, while engineering mix designs are commonly controlled more precisely by mass. This calculator follows the ratio parts and bulk density you enter for planning. It should not be treated as a substitute for a certified batch design.
The ratio calculation produces cement volume. Converting that volume to kilograms requires a bulk density assumption. Loose cement can have a different bulk density depending on handling and compaction, so use the value appropriate to your calculation method rather than treating one number as universal.
Moist sand can occupy a different bulk volume from dry sand because water films separate the particles. This can affect site batching by volume. The calculator does not automatically correct sand volume for moisture or bulking, so practical batching may need adjustment.
Coarse aggregate can carry surface moisture that contributes water to the mix. If water control matters, total batch water should consider moisture already present in the aggregates. The simple water estimate on this page does not make that correction automatically.
Adding excess water can change concrete performance. Do not keep adding water simply to make mixing easier unless the approved mix or project guidance allows it. The calculator's water figure is only the arithmetic result of the water-cement ratio you enter.
When mixing several batches, measure materials consistently from batch to batch. The Batch Volume mode can help scale the total quantity, but practical quality depends on repeating the same material proportions and water control for every batch.
A mixer should not be overloaded. The nominal drum size is not always the same as the practical batch volume. Confirm the manufacturer's usable batch capacity before deciding how much concrete to mix at one time.
Hand mixing may suit very small quantities, while a mechanical mixer can improve consistency and productivity for repeated batches. The calculator does not change material proportions based on mixing method; it only estimates total quantities.
Small site-mixed jobs can lose material through measuring, loading, mixer residue and placing. The waste field gives you a visible allowance. Keep it separate from the ratio so the actual material proportions remain clear.
Whole-bag rounding means the purchased cement mass may be slightly higher than the theoretical calculation. That is normal for planning. Keep unused cement protected from moisture and follow manufacturer storage instructions.
Bulk suppliers may sell sand and aggregate by volume or mass. If your supplier quotes tonnes rather than cubic metres, a separate material density is needed to convert the calculator's volume result into mass. Do not assume one universal tonne-per-cubic-metre conversion.
A ratio with a larger cement share will allocate more of the dry volume to cement and less to sand or aggregate. That does not automatically mean it is the correct or strongest mix for the project because strength and durability depend on more than simple volumetric proportions.
As concrete volume increases, site mixing can require many batches and significant labour. Compare the total cement, sand, aggregate and labour effort with a ready-mix option. Use the Concrete Order Calculator when you want to compare a final cubic-metre quantity with supplier order logistics.
For repeated small batches, decide the practical wet volume per batch, then multiply by the number of batches. The calculator can scale the total before splitting dry materials by the selected ratio.
If you do not yet know the wet concrete volume, calculate the project quantity first. Use the Concrete Quantity Estimator for slabs, footings, round pads and post holes, then bring the resulting cubic metres into this mixing calculator.
For very small projects, packaged premix may be simpler than measuring cement, sand and aggregate separately. The Concrete Bags Needed Calculator can estimate whole bags using the manufacturer-stated finished yield.
Use current product and bulk material prices. Cement bags, sand and aggregate can be priced differently by region, supplier, quantity and delivery method. The calculator's cost result is useful for comparing material scenarios, not predicting a complete construction invoice.
For Australian concrete industry information, see Cement Concrete & Aggregates Australia. For silica-related workplace information, review current Safe Work Australia guidance. For packaged cement or concrete products, use the manufacturer's technical data and mixing instructions.
The calculator's total includes only the cement bag price, sand price per cubic metre and aggregate price per cubic metre that you enter. A complete site-mixing budget may also include delivery, mixer hire, labour, water, admixtures, reinforcement, formwork, curing materials and waste handling.
Cement cost is calculated from whole bags after rounding. This is often more realistic for purchasing than multiplying a fractional bag quantity by a price because suppliers sell complete bags.
Sand cost is calculated from the estimated sand volume. Bulk suppliers may impose minimum quantities or delivery charges, so actual cost can be higher than a simple volume × rate calculation.
Aggregate cost uses the estimated aggregate volume. Different stone sizes and sources can have different rates. Use a price that matches the material required by the project or mix design.
Separate deliveries for cement, sand and aggregate can materially affect the budget. Some suppliers bundle delivery into the rate while others charge it separately. Keep delivery as an independent line item so you can compare suppliers accurately.
If a mixer is hired by the day or week, include that cost separately. Multiple small batches can take much longer than expected, so compare mixer hire and labour with ready-mix for larger volumes.
Site mixing requires measuring, loading, mixing, transporting, placing and cleaning. Labour can become a major part of total cost, especially when many batches are needed.
Plasticisers, retarders, accelerators, fibres, pigments and other products are not included. If the mix requires them, follow the manufacturer's dosage instructions and add the cost separately.
| Budget Item | Included In Calculator? | How To Estimate |
|---|---|---|
| Cement Bags | Yes | Whole bags × entered bag price |
| Sand | Yes | Sand volume × entered A$/m³ rate |
| Aggregate | Yes | Aggregate volume × entered A$/m³ rate |
| Water | Quantity Only | From entered water-cement ratio |
| Delivery | No | Use supplier quote |
| Mixer Hire | No | Use hire rate and expected duration |
| Labour | No | Estimate from crew size and mixing time |
| Admixtures | No | Use specified dosage and product price |
Material prices are only one part of a complete site-mixing budget.
Use related tools for wet concrete volume, bagged concrete and ready-mix ordering.
Common questions about mix ratio, dry volume, cement bags, sand, aggregate, water and material cost.
It starts with the wet concrete volume, applies the dry-volume factor you enter, then divides that dry volume according to the cement:sand:aggregate ratio.
Yes. Enter your own cement, sand and aggregate ratio parts. The calculator does not force one universal mix.
It is a planning multiplier used to convert finished wet concrete volume into a larger dry-material volume. The correct factor depends on the estimating method and materials, so it is editable.
Yes. Enter bag weight and cement bulk density. The calculator estimates cement mass and rounds up to whole bags.
Yes. Enter a water-cement ratio by mass and the calculator estimates water litres from cement mass.
No. It only uses the value you enter. Mix design, strength, durability, workability and water-cement ratio must follow the relevant project specification or mix design.
Yes. Enter the wet concrete volume in cubic metres and then enter the chosen dry-volume factor and material ratios.
Yes. Enter a waste percentage and the calculator increases the wet volume before calculating dry materials.
They are only placeholders. The real fields are blank, so typing 5 gives 5 rather than 05.
Yes. Enter cement cost per bag plus sand and aggregate rates per cubic metre. The calculator provides a simple material-only estimate.
No. Labour, delivery, mixer hire, pumping, reinforcement, formwork and other project costs are separate unless you add them elsewhere.
Yes. After calculating, you can download a PDF summary generated by ConcreteCreek.com.
Use current project specifications, product data and official safety guidance alongside any online mixing estimate.
Australian concrete industry and technical information.
Visit CCAANational silica hazard and workplace control information.
Read Silica GuidanceUse current cement, admixture and packaged-product technical data.
Use approved strength, durability, water-cement ratio and material requirements for the real project.