Estimate The Coarse Aggregate Quantity Associated With A Concrete Volume Using Your Own Mix Proportions, Dry-Volume Factor, Aggregate Density, Waste Allowance And Supplier Price. Start From Slab Dimensions, A Known Area, A Round Pour Or A Known Concrete Volume, Then See Aggregate Cubic Metres, Approximate Tonnes, Kilograms And Material-Only Cost.
Select The Measurement Method That Matches Your Project. The Calculator First Finds Wet Concrete Volume, Then Applies The Dry-Volume Factor And The Cement : Sand : Aggregate Parts You Enter To Estimate The Coarse Aggregate Share.
Your Aggregate Estimate Will Appear After You Press Calculate Aggregate.
| Mix Ratio Entered | 0 : 0 : 0 |
| Aggregate Share Of Dry Mix | 0% |
| Aggregate Before Allowance | 0.00 m³ |
| Approximate Aggregate Weight | 0 kg |
| Rounded Order Weight | 0.00 t |
The PDF Includes The Measurement Method, Concrete Volume, Dry-Volume Factor, Mix Parts, Aggregate Allowance, Bulk Density, Approximate Tonnes And Aggregate Material Cost.
The Figure Separates The Calculation Into Clear Steps So The Labels Stay Inside Their Cards On Desktop, Tablet And Mobile. Start With Wet Concrete Volume, Convert To The Dry-Material Volume Used By Your Method, Apply The Aggregate Share Of The Mix Parts, Then Convert Aggregate Cubic Metres To Tonnes Using The Density You Enter.
Keep The Main Numbers Separate: Concrete Volume, Dry-Material Volume, Aggregate Share, Aggregate Cubic Metres, Approximate Weight And Material Cost. This Makes It Easier To Check Each Assumption Before Ordering.
Calculate The Wet Concrete Volume From Project Measurements Or Enter A Known m³ Quantity.
Use Your Entered Cement, Sand And Aggregate Parts To Calculate The Aggregate Fraction.
Convert Aggregate Cubic Metres To Tonnes Using The Bulk Density You Enter.
Add A User-Controlled Percentage For Handling, Measurement Difference Or Ordering Buffer.
Use Your Own A$/t Supplier Price Instead Of A Fixed National Cost Assumption.
Save The Measurements, Mix Inputs, Quantity And Cost For Quote Or Planning Reference.
A concrete aggregate calculator can be useful when you already have a defined estimating method or nominal mix proportion and want to translate a concrete volume into an approximate coarse aggregate quantity. The calculation begins with the finished or wet concrete volume. For a rectangular slab, that is length × width × thickness after the thickness has been converted from millimetres to metres. For a round pad or cylindrical pour, use the area of the circle multiplied by depth. If a drawing, estimator or supplier has already given you the concrete volume in cubic metres, the geometry step can be skipped.
The next step is different from a basic Concrete Volume Calculator. Concrete is not simply a container filled with separate dry ingredients in exactly the same final volume. A mix-estimating method may therefore use a dry-volume factor before dividing the total dry material between cement, sand and coarse aggregate. Because estimating conventions and project documentation can differ, this calculator does not insert a hidden factor. You enter the factor that matches the method you have been instructed to use.
Measure the actual concrete shape rather than the excavation footprint if they are different. A slab that is 6 m long, 4 m wide and 100 mm thick uses 6 × 4 × 0.10 = 2.40 m³ before any separate project allowance. If there are thickened edges, beams, steps, pads, piers or other deeper areas, calculate those parts separately and add them to the main slab volume. For foundation-specific geometry, the Concrete Foundation Calculator may be more convenient.
Wet Concrete Volume (m³) = Length (m) × Width (m) × Thickness (m) × Quantity
A dry-volume factor is an estimating adjustment used by some nominal mix calculations to account for the relationship between loose dry ingredients and the finished compacted concrete volume. It should not be treated as a universal physical constant. Aggregate grading, particle shape, moisture, compaction, paste content, air content and the actual mix design all affect the relationship. Enter the factor specified by the method, coursework, estimator, mix sheet or procedure you are following.
If you are ordering commercial ready-mix concrete, you normally do not need to calculate the separate aggregate quantity at all. In that situation, work from the required concrete cubic metres and obtain a delivered price using the Concrete Cost Calculator or a supplier quote.
The ratio fields work as relative parts. If the inputs are 1 part cement, 2 parts sand and 4 parts coarse aggregate, the total is 7 parts and the aggregate fraction is 4 ÷ 7. If your documented ratio is different, enter those parts instead. The calculator does not assume that one ratio is suitable for every slab, footing, driveway, post hole or structural element.
Aggregate Share = Aggregate Parts ÷ (Cement Parts + Sand Parts + Aggregate Parts)
The aggregate allowance field is optional. It can be used when your estimating process requires a small buffer for handling loss, measurement uncertainty or supplier ordering increments. Do not automatically add a large percentage to every job. If the concrete volume already includes a separate project waste allowance, check that you are not unintentionally adding the same contingency twice.
Bulk density is needed to convert volume to weight. The correct value depends on the exact aggregate product, grading, particle shape, moisture condition and how the supplier reports the material. That is why the density field starts empty instead of using a fixed national number. Ask the quarry, landscape supplier or concrete materials supplier for the bulk density that applies to the aggregate you are pricing.
Approximate Tonnes = Aggregate Volume (m³) × Bulk Density (t/m³)
Coarse aggregate is not one uniform product. Concrete may use crushed rock, natural gravel or other approved aggregate with different nominal sizes and grading envelopes. The distribution of particle sizes influences packing, workability, paste demand and performance. A quantity calculator can estimate bulk volume or weight, but it cannot determine whether a particular aggregate grading is suitable for the mix, reinforcement spacing, pumping method, finish or exposure conditions.
If your goal is simply to estimate loose stone for a landscaping or drainage layer rather than aggregate as a concrete constituent, use the Gravel Estimator. For compacted granular material under paving, the Paver Base Calculator is a better match because it focuses on finished base depth and compaction rather than concrete mix proportions.
For a slab, measure length and width in metres and thickness in millimetres. Convert thickness to metres by dividing by 1000. The slab mode does this conversion automatically. If the slab contains recesses, edge beams or thickened strips, calculate those separately. A single average thickness can understate the volume when parts of the slab are deeper than the main field.
| Slab Thickness | Depth In Metres | Wet Concrete Per 10 m² | Wet Concrete Per 50 m² |
|---|---|---|---|
| 75 mm | 0.075 m | 0.75 m³ | 3.75 m³ |
| 100 mm | 0.100 m | 1.00 m³ | 5.00 m³ |
| 125 mm | 0.125 m | 1.25 m³ | 6.25 m³ |
| 150 mm | 0.150 m | 1.50 m³ | 7.50 m³ |
| 200 mm | 0.200 m | 2.00 m³ | 10.00 m³ |
Round concrete uses π × radius² × depth. The calculator asks for diameter, so it divides the diameter by two internally to get the radius. This can be useful for round equipment pads, some pier-style pours and other cylindrical shapes. For actual post holes where the post itself displaces part of the concrete, the dedicated Concrete Post Hole Calculator provides more relevant inputs.
The material cost shown here multiplies the rounded aggregate tonnes by the A$/tonne rate you enter. It is not the total cost of making or placing concrete. Cement, sand, admixtures, water, batching, delivery, labour, reinforcement, pumping, formwork, excavation and finishing can all be separate costs. If you are comparing complete project quotes, separate each cost category instead of assuming the aggregate line represents the concrete budget.
A reliable estimate uses current information for the exact material being purchased. Ask for aggregate bulk density, sale unit, minimum order quantity, delivery charges and whether the quoted rate includes GST or other fees. For broader Australian concrete industry information, you can consult Cement Concrete & Aggregates Australia. When cutting, grinding or handling materials that may generate respirable crystalline silica dust, review relevant workplace guidance from Safe Work Australia.
The examples below show the sequence of the calculation, not recommended mix designs. The dry-volume factors, mix parts and densities are illustrative inputs only. Replace them with the values that apply to your own documented estimating method and material.
| Example | Wet Concrete | Dry Factor | Mix Parts C:S:A | Aggregate Share |
|---|---|---|---|---|
| Illustrative Slab A | 2.40 m³ | User Entered | 1 : 2 : 4 | 4 ÷ 7 |
| Illustrative Slab B | 5.00 m³ | User Entered | 1 : 3 : 6 | 6 ÷ 10 |
| Illustrative Pad | 0.80 m³ | User Entered | 2 : 3 : 5 | 5 ÷ 10 |
| Known Volume | 10.00 m³ | User Entered | Per Documents | Aggregate ÷ Total |
Supplier quotes can be difficult to compare when one price is per tonne, another includes delivery, and another uses a different product description or minimum load. Start by fixing the quantity assumptions: the same concrete volume, the same mix-part inputs, the same aggregate allowance and the same density. Then compare the commercial details separately.
Keep Geometry, Mix Proportion, Density And Commercial Ordering Rules Separate So You Can See Which Assumption Changes The Final Tonnes.
Start With The Correct Finished Concrete Volume.
Use The Cement, Sand And Aggregate Parts From Your Estimating Method.
Use Product-Specific Density When Converting Aggregate Volume To Weight.
Add Delivery And Minimum-Order Rules Outside The Material Rate If Required.
Answers To Common Questions About Aggregate Parts, Cubic Metres, Tonnes, Density, Waste And Concrete Mix Estimating.
It Estimates The Coarse Aggregate Share Associated With A Concrete Volume Using The Dry-Volume Factor, Cement Parts, Sand Parts, Aggregate Parts, Allowance And Bulk Density You Enter.
No. It Deliberately Leaves The Mix-Part Fields Empty. Enter The Ratio Required By Your Approved Documentation Or The Estimating Method You Are Following.
The Light 0 Is A Placeholder Only. The Actual Numeric Field Is Empty, So If You Type 5 The Field Shows 5 Rather Than 05.
Some Nominal Mix Estimating Methods Convert Finished Wet Concrete Volume To An Approximate Dry-Material Volume Before Dividing It By Mix Parts. The Factor Is User Entered Because It Is Not A Universal Constant.
Add The Cement, Sand And Aggregate Parts Together, Then Divide The Aggregate Parts By That Total. The Result Is The Aggregate Fraction Of The Dry-Material Volume Used By The Calculator.
Multiply Aggregate Cubic Metres By The Bulk Density In Tonnes Per Cubic Metre. Use Supplier Data For The Exact Product Whenever Possible.
No. Bulk Density Can Change With Rock Type, Grading, Particle Shape, Moisture And The Way The Material Is Measured Or Stockpiled.
Only If Your Estimating Process Requires It. Check Whether Your Concrete Volume Or Other Inputs Already Include A Contingency So You Do Not Add The Same Allowance Twice.
You Can Use It For Educational Or Material-Breakdown Estimating If You Know The Relevant Inputs, But Ready-Mix Is Normally Ordered By Concrete Volume And Mix Specification Rather Than By Separately Calculating Aggregate.
No. It Is A Quantity Calculator. Structural Strength, Durability, Exposure Classification, Water-Cement Ratio, Cementitious Content, Admixtures And Aggregate Grading Require The Appropriate Project Specification And Professional Or Supplier Guidance.
No. The Cost Result Uses Only The Rounded Tonnes Multiplied By The A$/tonne Rate You Enter. Add Delivery, Minimum Load, Handling Or Other Supplier Fees Separately If They Apply.
The PDF Includes The Measurement Method, Wet Concrete Volume, Dry-Volume Factor, Mix Parts, Aggregate Share, Allowance, Density, Rounded Tonnes And Material Cost.
Use Supplier Product Data, Project Documentation And Appropriate Australian Industry Or Safety Guidance Alongside Any Online Quantity Estimate.
Australian Concrete And Aggregate Industry Information And Technical Resources.
Visit CCAANational Guidance About Crystalline Silica Hazards And Workplace Controls.
Read Silica GuidanceUse The Approved Mix Specification Or Supplier-Designed Concrete Product For Structural Work.
Confirm Product Grading, Bulk Density, Sale Unit, Minimum Load, Delivery And Current Price Before Ordering.