Calculate Concrete Volume In Cubic Metres For Slabs, Pads, Cylinders, Strip Footings And Projects Where You Already Know The Surface Area. Enter Your Own Measurements, Add A Waste Allowance, Estimate 20 Kg Bags And Apply An Editable Concrete Rate Without Relying On A Fixed Price.
Select The Shape Or Measurement Method That Best Matches Your Project. All Numeric Entries Start At 0 So You Can Build The Estimate From Your Own Measurements.
Your Result Will Appear Here After You Press Calculate Concrete Volume.
The PDF Includes The Site Name, Selected Method, Measurements, Base Volume, Waste Allowance, Rounded Order Volume, Litres, Bag Estimate And Concrete-Only Cost.
A Clear Concrete Volume Calculation Uses Three Dimensions. For A Rectangular Pour, Convert The Thickness To Metres And Multiply Length × Width × Depth. The Cards Below Stay Inside The Figure On Desktop, Tablet And Mobile.
The Calculator Keeps Geometry, Waste, Order Rounding, Bags And Cost Separate So You Can Understand Where Each Number Comes From.
See The Exact Geometric Volume From The Measurements You Enter Before Any Contingency Is Added.
Add Your Own Percentage For Irregular Excavation, Form Variations, Spillage Or Measurement Uncertainty.
Convert The Final Rounded Cubic Metre Quantity To Litres Using 1 m³ = 1000 Litres.
Estimate Whole Bags Only After Entering The Actual Yield Per Bag From The Product Data Sheet.
Apply Your Own Local A$/m³ Rate Instead Of Treating A Generic Online Price As A Supplier Quote.
Save The Main Quantity And Cost Inputs In A Simple PDF For Quote Comparison Or Project Notes.
A Concrete Volume Calculator Helps Turn Real Project dimensions into a quantity that can be discussed with a ready-mix supplier or compared with packaged concrete yield. The key idea is simple: concrete is three-dimensional. Square metres describe surface area, but cubic metres describe the actual volume of material. For a rectangular slab, this means multiplying length, width and depth after every dimension has been converted to compatible units.
For many Australian projects, length and width are measured in metres while slab thickness, footing width and footing depth are commonly recorded in millimetres. That mix of units is convenient on site but must be normalised before multiplication. A depth of 100 mm is 0.10 m, 125 mm is 0.125 m and 150 mm is 0.15 m. If millimetres are accidentally treated as metres, the result can be wrong by a very large factor.
Volume (m³) = Length (m) × Width (m) × Depth (m)The Slab / Rectangle option is useful when the pour has a regular length, width and thickness. Measure the inside dimensions of the formwork or use the dimensions shown on suitable project documentation. Enter length and width in metres, then enter the thickness in millimetres. The calculator converts the thickness to metres before multiplying the three dimensions.
For example, a 6 m × 4 m slab at 100 mm thick has a base volume of 2.40 m³. If the slab includes thickened edges, integral beams, steps or other deeper sections, a simple uniform slab calculation may not capture all of the concrete. Those extra shapes should be calculated separately and added to the base slab quantity.
Round concrete requires the area of a circle before depth or height is included. The Round / Cylinder option divides the entered diameter by two to obtain the radius, squares that radius, multiplies by π and then multiplies by depth. This is useful for round pads, circular bases and cylindrical concrete elements where the concrete occupies the full cylinder.
Volume (m³) = π × (Diameter ÷ 2)² × DepthIf you are calculating a post hole where a post displaces part of the concrete, use the dedicated Concrete Post Hole Calculator rather than assuming the entire cylinder is concrete. That tool is better suited to hole geometry and post displacement.
Strip footings are long rectangular volumes. The basic formula is still length × width × depth, but the calculator lets you enter the total footing length in metres while keeping width and depth in millimetres. If a foundation has sections with different footing sizes, calculate each size separately. Do not average substantially different widths or depths unless that approximation is appropriate for your planning purpose.
For broader foundation planning, including pad footings and foundation-specific shapes, the Concrete Foundation Calculator can be a more direct starting point.
Sometimes the surface area has already been measured or calculated in square metres. In that case you do not need to re-enter length and width. Select Area × Thickness, enter the known area in m² and the concrete depth in millimetres. The calculator converts the depth to metres and multiplies area by depth. This is particularly convenient for irregular plan shapes where the area has already been established from drawings, CAD, surveying software or a separate area calculation.
Volume (m³) = Area (m²) × Depth (m)Ready-mix concrete quantities are commonly discussed in cubic metres. This makes m³ the practical output for many larger pours. A cubic metre is a three-dimensional cube measuring one metre long, one metre wide and one metre high. It is also equal to 1000 litres. The litre conversion in the results is useful for understanding scale, but supplier ordering practices, minimum loads and rounding can differ, so the calculator keeps its order-rounding control editable.
A drawing-based geometric volume assumes the real excavation, base and forms match the planned dimensions exactly. On site, trenches can widen, subgrades can have low spots, forms can vary, concrete can remain in a pump line or wheelbarrow, and small amounts can be lost during placement. A contingency or waste allowance helps account for these differences, but there is no single percentage that is correct for every project.
Use the waste field as a planning input rather than an automatic rule. A well-controlled formed slab may need a different allowance from rough excavation. If the project is critical or the order is large, confirm the final quantity with the concrete supplier, builder, estimator or other responsible project professional before placing the order.
Zero defaults keep the Concrete Volume Calculator neutral. A pre-filled length, price or waste percentage can look like a recommendation even when it is only an example. Starting from zero makes it clearer that the result should be built from your own project dimensions, your chosen waste allowance, your product yield and your local concrete quote.
The calculator includes a 20 kg bag estimate because packaged concrete is useful for smaller jobs. However, two products with the same bag weight can have different yields because their formulations and water requirements differ. Enter the yield printed on the exact manufacturer data sheet. The calculator divides the rounded order volume by that yield and rounds up to the next whole bag.
For larger continuous pours, a very high bag count can also be a practical warning that ready-mix concrete may deserve comparison. Mixing, placing and finishing hundreds of bags can involve substantial time and labour even if the arithmetic is straightforward.
A volume calculation answers “how much space will concrete occupy?” It does not answer “how thick should the slab be?” or “what strength, reinforcement or footing dimensions are required?” Those decisions depend on the project, loading, soil, exposure, design documentation and applicable requirements. Use the calculator after the required geometry is known, not as a substitute for determining that geometry.
The table shows simple geometric examples before any project-specific waste allowance or supplier rounding. It is intended to demonstrate the formulas, not to prescribe dimensions for your project.
| Concrete Shape | Example Dimensions | Calculation | Base Volume | Litres |
|---|---|---|---|---|
| Small Slab | 3 m × 2 m × 100 mm | 3 × 2 × 0.10 | 0.60 m³ | 600 L |
| Driveway Section | 6 m × 3 m × 100 mm | 6 × 3 × 0.10 | 1.80 m³ | 1,800 L |
| Thicker Rectangular Pad | 4 m × 3 m × 150 mm | 4 × 3 × 0.15 | 1.80 m³ | 1,800 L |
| Round Pad | 2 m Diameter × 150 mm | π × 1² × 0.15 | 0.47 m³ | 471 L |
| Strip Footing | 20 m × 300 mm × 300 mm | 20 × 0.30 × 0.30 | 1.80 m³ | 1,800 L |
| Known Area | 35 m² × 100 mm | 35 × 0.10 | 3.50 m³ | 3,500 L |
A volume estimate becomes more useful when every supplier is pricing the same quantity and the same scope. First calculate the project geometry consistently. Then add the waste allowance you intend to use and note the rounded order volume. When requesting quotes, ask whether the quoted rate is per cubic metre and whether the total includes delivery, minimum-load charges, waiting time, pumping, surcharges, testing or other services relevant to the job.
The calculator’s cost field deliberately accepts your own A$/m³ rate. This avoids presenting a national example price as though it were a current local quote. Concrete pricing can vary with location, mix, quantity, access, timing and supplier. For a broader project budget after the cubic metres are known, use the Concrete Cost Calculator, which is designed to separate additional cost items from the concrete-only quantity.
If one quote is based on 3.0 m³ and another is based on 3.5 m³, the total prices are not directly comparable. Use the same dimensions, same waste allowance and same rounding basis first. Keep notes about any separate beams, footings or thickened areas so they do not disappear between versions of the estimate.
A per-m³ figure may represent the concrete itself while other charges appear separately. Ask for a delivered project quote and read the supplier terms. The cheapest headline rate is not necessarily the lowest final invoice if access, minimum quantities or service fees differ.
The required concrete specification can affect price, but the Concrete Volume Calculator does not choose that specification. Quote requests should use the strength, slump, aggregate or other requirements stated by the responsible designer, builder, engineer or project documents.
The calculator can round the planning quantity to 0.01, 0.05 or 0.10 m³. That is a mathematical convenience, not a promise that a supplier accepts every increment. Ask the supplier how orders are rounded and whether minimum-load or small-load rules apply.
Once you have a useful estimate, download the PDF. It creates a simple record of the selected method, main dimensions, waste allowance, volume and rate. Saving each major version can make it easier to understand why two quotes were based on different quantities later.
These relationships are mathematical conversions. They do not determine the correct structural size or concrete specification for a project.
A cube measuring 1 m × 1 m × 1 m.
One cubic metre equals one thousand litres.
100 millimetres equals 0.10 metres.
Square metres multiplied by depth in metres gives m³.
Answers To Common Questions About Cubic Metres, Litres, Slab Thickness, Waste, Bags And Concrete Ordering.
For A Rectangular Pour, Multiply Length In Metres By Width In Metres By Depth In Metres. If The Depth Is In Millimetres, Divide It By 1000 Before Multiplying.
One Cubic Metre Is Equal To 1000 Litres. The Calculator Shows The Rounded Order Volume In Both Cubic Metres And Litres.
One Square Metre At 100 mm, Or 0.10 m, Thick Has A Volume Of 0.10 m³, Which Is 100 Litres.
Ten Square Metres At 100 mm Thick Has A Base Volume Of 1.00 m³ Before Any Waste Allowance Or Supplier Rounding.
Ten Percent Is Sometimes Used As A Planning Allowance, But It Is Not A Universal Rule. The Right Contingency Depends On Form Accuracy, Excavation, Site Conditions And The Nature Of The Pour. Enter The Percentage Appropriate To Your Own Estimate.
Only If You Include Their Volume. A Uniform Slab Calculation Does Not Automatically Add Deepened Beams, Steps Or Edges. Calculate Those Additional Sections Separately And Add Them To The Project Quantity.
Yes For Volume Estimating When You Know The Required Area Or Length, Width And Thickness. The Calculator Does Not Determine The Correct Driveway Thickness, reinforcement or concrete specification.
Yes. Select Strip Footing For A Regular Rectangular Footing Run. For More Foundation-Specific Shapes, Use The Concrete Foundation Calculator.
A Full Cylinder Can Be Estimated With The Round Option. When A Post Occupies Part Of The Hole, The Dedicated Concrete Post Hole Calculator Is Better Because It Can Account For Post Displacement.
There Is No Safe Universal Bag Count Based On Weight Alone. Enter The Yield Stated By The Manufacturer For The Exact Product, Then Divide The Required Volume By That Yield And Round Up.
Zero Defaults Avoid Making Example Dimensions, prices or waste percentages look like recommendations. Enter Your Own Project Values Before Calculating.
Not Necessarily. The Rate Field Is Simply The Number You Enter. Ask Your Supplier Whether A Quote Includes Delivery, Minimum Loads, Waiting Time, Pumping Or Other Applicable Charges.
The PDF Includes The Site Name, Selected Calculation Method, Key Measurements, Waste Allowance, Base Volume, Rounded Order Volume, Litres, Bag Estimate, Concrete Rate And Concrete-Only Cost.
Use Current Supplier Information, Product Data Sheets And Appropriate Safety Guidance Alongside Any Online Quantity Estimate.
Australian Industry Information And Concrete Resources.
Visit CCAANational Information About Silica Hazards And Safe Work Practices.
Read Silica GuidanceExample Manufacturer Information For Packaged Concrete Products.
View Product InformationConfirm Final Quantity, Mix, Delivery Access, Minimum Load And Service Fees Before Ordering.