Estimate The Concrete Needed For Strip Footings, Slab Foundations, Pad Footings And Round Foundation Piers. Enter Your Own Metric Dimensions, Add A Practical Waste Allowance, Estimate Concrete Cost And Save A Clear PDF Result For Planning Or Quote Comparison.
Select The Foundation Shape That Best Matches Your Project. The Calculator Converts Millimetres To Metres Where Needed And Returns Concrete Volume In Cubic Metres.
Your Result Will Appear After You Press Calculate Foundation Concrete.
The PDF Includes The Site Name, Foundation Type, Measurements, Waste Allowance, Base Volume, Rounded Order Volume, Optional Bag Estimate And Concrete-Only Cost.
A Strip Footing Is A Rectangular Concrete Volume. Convert Width And Depth From Millimetres To Metres, Then Multiply Them By The Total Footing Length.
The Figure Is Illustrative Only. Use The Actual Foundation Dimensions From Your Project Documents.
Keep The Important Quantity And Budget Numbers Separate So You Can See The Geometric Volume, Waste Allowance, Rounded Order Quantity And Optional Cost Estimate.
Calculate The Base Concrete Quantity In Cubic Metres From Your Measurements.
Add A User-Selected Percentage For Real-World Variation In Excavation And Formwork.
Round The Planning Quantity To A Practical Increment That You Select.
Enter Your Own Supplier Rate Per Cubic Metre For A Concrete-Only Budget Estimate.
Save The Main Foundation Measurements And Estimate For Easier Quote Comparison.
All Numeric Inputs Start At Zero So The Result Comes From Your Own Project Data.
A Concrete Foundation Calculator turns foundation dimensions into an estimated concrete volume. The basic mathematics is straightforward, but the quality of the estimate depends on the measurements entered. Foundation work can include strip footings under walls, slab-on-ground foundations, isolated pad footings beneath posts or columns, and round piers or bored holes. Each shape needs the correct volume formula.
The calculator is designed for quantity planning rather than structural design. It does not decide how wide or deep a footing should be, how much reinforcement is required, what concrete strength should be specified, or whether a particular foundation system is suitable for the soil and building. Those decisions should come from appropriate project documents, site information, engineering and applicable requirements.
Concrete Volume (m³) = Total Length (m) × Width (m) × Depth (m) × QuantityStrip footings are usually treated as long rectangular prisms for volume estimating. If width and depth are measured in millimetres, divide each value by 1000 before multiplying. For example, a 300 mm width becomes 0.30 m. If the project has several identical runs, the quantity field can multiply the result; otherwise enter the combined total length and use one run.
Volume (m³) = Length (m) × Width (m) × Thickness (m) × QuantityA slab foundation estimate needs more than floor area because thickness changes the cubic metres significantly. A 100 mm slab uses 0.10 m³ for every square metre of plan area, while a thicker slab uses more. Thickened edges, internal beams, ribs and drop panels should be calculated separately if they are not already included in the simple slab thickness.
Volume (m³) = Length × Width × Depth × Number Of PadsFor isolated rectangular or square pad footings, convert all millimetre dimensions to metres and multiply by the number of identical pads. If pad sizes vary, calculate each size group separately and add the volumes together. This approach is usually clearer than averaging unlike footing dimensions.
Volume (m³) = π × Radius² × Depth × QuantityFor round bored piers or holes, divide the diameter by two to get the radius. Convert the diameter and depth to metres before applying the cylinder formula. A post, reinforcement cage or other permanent element can displace some concrete, but the correct displacement should be calculated from actual geometry when it materially affects the order.
Foundation drawings and site measurements often use millimetres for widths, depths and slab thicknesses. Concrete volume is normally easier to express in cubic metres, so the dimensions must use consistent units before multiplication.
| Foundation Dimension | Metres | Typical Use In Calculation |
|---|---|---|
| 200 mm | 0.200 m | Slab / Footing Dimension |
| 300 mm | 0.300 m | Footing Width Or Depth |
| 450 mm | 0.450 m | Pad / Footing Dimension |
| 600 mm | 0.600 m | Pier Diameter Or Depth |
| 1000 mm | 1.000 m | One Metre |
There is no single waste percentage that suits every foundation. Excavated trenches can be wider than drawings, sides can collapse, the base can be uneven, forms can move and site dimensions can differ from the idealised geometry. The calculator therefore leaves the allowance editable. A tightly formed footing may need a different contingency from an irregular trench in variable ground.
Waste allowance should be treated as a planning input, not as a substitute for measuring the real excavation. If the site has already been excavated, measuring the actual formed or excavated dimensions can provide a more useful estimate than relying only on nominal dimensions.
These examples show how the formulas work. They are arithmetic examples only and do not recommend foundation dimensions.
| Foundation Type | Example Dimensions | Base Formula | Base Volume | With 10% Example Allowance |
|---|---|---|---|---|
| Strip Footing | 20 m × 300 mm × 300 mm | 20 × 0.30 × 0.30 | 1.80 m³ | 1.98 m³ |
| Slab Foundation | 8 m × 6 m × 100 mm | 8 × 6 × 0.10 | 4.80 m³ | 5.28 m³ |
| 4 Pad Footings | 600 × 600 × 300 mm | 0.60 × 0.60 × 0.30 × 4 | 0.432 m³ | 0.475 m³ |
| 8 Round Piers | 300 mm Dia × 600 mm Deep | π × 0.15² × 0.60 × 8 | 0.339 m³ | 0.373 m³ |
A real foundation can combine several concrete elements. For example, a slab may sit within edge beams while isolated pads support posts. Calculate each different geometry independently and then combine the cubic metres. Separating components makes it easier to check the arithmetic and identify where a large quantity originates.
A foundation quote can include far more than the ready-mix concrete itself. Excavation, spoil removal, formwork, reinforcement, vapour barriers, pumping, labour, testing, access equipment and finishing can all be separate or bundled items. The cost field in this calculator deliberately estimates only the concrete quantity multiplied by the rate you enter, so it remains clear what the number represents.
When comparing quotes, first check whether each contractor or supplier is pricing the same foundation scope. One quote may include excavation and reinforcement while another may list only supply and placement. Compare like with like rather than assuming the lowest headline figure includes the same work.
Once you are comfortable with the quantity, enter the same order volume when reviewing different concrete rates. This makes price differences easier to understand. If a supplier uses minimum-load charges, delivery fees, waiting time, pump charges or other services, keep those separate from the base A$/m³ rate unless the quote explicitly combines them.
Concrete pricing can depend on the required mix, location, order size, delivery conditions and services. Replace the calculator's zero rate with the actual figure supplied for your project rather than relying on a generic internet number. For broader budgeting, the separate Concrete Cost Calculator can help organise additional project cost inputs.
A quote may show a certain number of cubic metres, but that number does not validate the foundation design. The dimensions and concrete specification should be checked against the project documents. If a measured quantity differs materially from the drawings or quote, investigate the reason before ordering.
Answers To Common Questions About Foundation Volume, Footings, Slabs, Piers, Waste And Concrete Ordering.
Choose the foundation shape, convert all dimensions to consistent metre units, and use the correct volume formula. Rectangular footings and slabs use length × width × depth; round piers use π × radius² × depth.
No. It estimates concrete volume from dimensions you enter. Foundation dimensions, reinforcement, concrete strength and structural details should come from appropriate project documents, engineering, site information and applicable requirements.
Multiply the total footing length in metres by the footing width in metres and depth in metres. Multiply by the number of identical runs if you have entered one-run length rather than combined length.
Multiply slab length by slab width by slab thickness, with all dimensions expressed in metres. Calculate thickened edges or beams separately when they are deeper than the main slab.
Convert the diameter to metres, divide it by two to obtain the radius, then calculate π × radius² × depth × number of piers.
Zero defaults prevent example measurements or prices from being mistaken for your project. Enter the actual dimensions and any rate you want to use before calculating.
A contingency can help account for real variation, but there is no single correct percentage for every site. Base the allowance on actual excavation, formwork accuracy, site conditions and ordering requirements.
Yes. Enter a supplier rate per cubic metre and the calculator multiplies it by the rounded order volume. The result is concrete-only and does not automatically include excavation, steel, formwork, pumping, labour or other project costs.
The calculator can estimate a bag count only when you enter the manufacturer's stated yield per bag. Whether bagged or ready-mix concrete is appropriate depends on the project specification, quantity, placement requirements and practical site conditions.
The PDF records the selected foundation type, measurements, base volume, waste allowance, rounded order volume, optional bag estimate and concrete-only cost, with ConcreteCreek.com shown as the generator.
Use Current Project Documents, Supplier Information And Authoritative Guidance Alongside Any Online Foundation Estimate.
Australian Industry Information And Technical Concrete Resources.
Visit CCAAAustralian Building Code Information And NCC Resources.
Visit NCCNational Guidance About Silica Hazards And Work Health And Safety.
Read Silica GuidanceConfirm Structural Details, Final Quantity, Mix Specification, Delivery Access And Ordering Rules Before Placement.