Calculate How Much Concrete You Need For A Straight Curb, Combined Curb And Gutter, Curved Curb Or A Known Concrete Volume. Enter Metric Measurements, Add A Waste Allowance, Estimate 20 Kg Concrete Bags And Build A Quick Concrete-Only Cost Estimate.
Select The Shape That Matches Your Project. Every Numeric Entry Starts At 0, And Results Stay Hidden Until You Press Calculate Concrete Curb.
Your Result Will Appear Here After You Press Calculate Concrete Curb.
The PDF Includes The Site Name, Curb Type, Measurements, Waste Allowance, Volume, Bag Estimate And Concrete-Only Cost.
A Straight Curb Can Be Treated As A Long Rectangular Prism. Convert The Width And Height From Millimetres To Metres, Then Multiply The Cross-Section By The Total Length.
Use The Tool For Simple Quantity Planning Before Comparing Supplier Quotes, Bagged Concrete, Formwork And Labour Requirements.
Calculate The Base Concrete Quantity In Cubic Metres For Straight Or Curved Sections.
Add A Percentage For Small Differences In Forms, Excavation And Placement.
Combine The Curb Section And Gutter Slab Into One Concrete Volume Estimate.
Use Radius And Angle To Calculate Arc Length Before Applying The Cross-Section.
Convert The Concrete Volume Into Whole Bags When You Enter A Product Yield.
Enter Your Own A$/m³ Rate To Build A Concrete-Only Cost Estimate.
A Concrete Curb Calculator estimates the volume of concrete needed to build a curb, kerb or combined curb-and-gutter section. The core method is to calculate the cross-sectional area of the concrete shape and multiply it by the total length. For a straight rectangular curb, that becomes length × width × height. For a curved curb, the cross-section is multiplied by arc length instead of straight-line length.
The calculator separates straight curbs, curb and gutter sections, curved curbs and known volume. Width and height can be entered in millimetres while length and radius use metres. The final quantity is shown in cubic metres so it can be compared with concrete supplier quotes or converted into bagged concrete.
Volume (m³) = Length (m) × Width (m) × Height (m)For example, a curb 10 metres long, 150 mm wide and 300 mm high uses 10 × 0.15 × 0.30 = 0.45 m³ before any extra allowance. If you need a general slab or footing calculation instead, use the internal Concrete Calculator Australia.
Concrete curb drawings often show width and height in millimetres. Divide millimetres by 1000 before using them in a cubic-metre formula. A 100 mm dimension is 0.10 m, 150 mm is 0.15 m, 200 mm is 0.20 m and 300 mm is 0.30 m.
| Dimension | Metres | Use In Formula |
|---|---|---|
| 100 mm | 0.100 m | 0.100 |
| 150 mm | 0.150 m | 0.150 |
| 200 mm | 0.200 m | 0.200 |
| 250 mm | 0.250 m | 0.250 |
| 300 mm | 0.300 m | 0.300 |
A combined curb and gutter contains more than one rectangular component. Calculate the curb cross-sectional area and gutter slab area separately, add them together, then multiply the combined area by total length.
Volume = Length × [(Curb Width × Curb Height) + (Gutter Width × Gutter Thickness)]This simplified formula works for rectangular sections. Real civil details can include slopes, channels, chamfers, rebates or thickened edges. When the project drawing shows a more complex shape, calculate the actual cross-sectional area from the drawing rather than forcing it into a simple rectangle.
A curved curb uses arc length. Enter the curve radius and central angle. A full circle is 360 degrees, a half circle is 180 degrees and a quarter circle is 90 degrees. The calculator finds the arc length and then multiplies it by curb width and height.
Arc Length = 2 × π × Radius × (Angle ÷ 360)Volume = Arc Length × Curb Width × Curb HeightUse the radius reference required by the actual design. A wide curb has different inner and outer arc lengths, so detailed civil work should follow the project geometry rather than a simplified estimate.
Concrete per linear metre depends on the curb cross-section. A 150 mm wide × 300 mm high curb has a cross-sectional area of 0.15 × 0.30 = 0.045 m², so each metre contains 0.045 m³ of concrete before waste.
| Example Curb Size | Cross-Section Area | Concrete Per 1 m | Concrete Per 10 m | Concrete Per 50 m |
|---|---|---|---|---|
| 100 × 200 mm | 0.020 m² | 0.020 m³ | 0.200 m³ | 1.000 m³ |
| 150 × 250 mm | 0.0375 m² | 0.0375 m³ | 0.375 m³ | 1.875 m³ |
| 150 × 300 mm | 0.045 m² | 0.045 m³ | 0.450 m³ | 2.250 m³ |
| 200 × 300 mm | 0.060 m² | 0.060 m³ | 0.600 m³ | 3.000 m³ |
| 200 × 400 mm | 0.080 m² | 0.080 m³ | 0.800 m³ | 4.000 m³ |
These are geometry examples, not standard curb dimensions. Use the dimensions required by the actual project documents or authority detail.
There is no single percentage that suits every curb project. Neat formwork can be measured closely, while hand-formed sections, irregular subgrade and multiple transitions can create more variation. This calculator starts at 0 so the allowance is based on the actual job rather than a preset assumption.
Small landscape curbs, garden edging and repair sections may be practical with bagged concrete. Enter the yield printed on the exact product data sheet. The calculator divides the required volume by that yield and rounds up to whole bags. For more detailed bag planning, use the Concrete Bag Calculator.
The cost field multiplies the calculated concrete volume by the A$/m³ rate you enter. It is a concrete-only estimate. Excavation, formwork, subbase, reinforcement, dowels, labour, finishing, curing, traffic control and disposal are separate unless your supplier or contractor quote says otherwise. For broader budgeting, see the Concrete Cost Calculator.
Two curbs can have the same length but require very different concrete volumes if their widths and heights differ. A linear-metre quantity only makes sense when the cross-section is also defined. That is why this calculator asks for dimensions instead of relying on a fixed quantity per metre.
The same volume principle can be applied to driveway edges, landscape curbs, garden borders and simplified roadway curb sections. Civil and public works curbs can have authority-specific profiles, slopes, drainage details, reinforcement and accessibility requirements that are outside the scope of a simple volume calculator.
This tool estimates quantity only. It does not select curb profile, foundation preparation, reinforcement, concrete strength, joints, drainage grade, gutter slope, tie-ins, dowels, curing method, traffic loading or compliance requirements. Use current project drawings and specifications. For general Australian concrete information, see Cement Concrete & Aggregates Australia. For silica safety information, consult Safe Work Australia.
Length, Cross-Section, Curve Geometry And Waste Allowance Determine The Main Quantity. Structural Design Remains Separate.
Measure The Actual Run Or Calculate Arc Length For A Curve.
Convert Width To Metres Before Multiplying Volume.
Use The Required Concrete Section Height.
Add Only The Contingency Appropriate To The Job.
These Examples Show Geometry Only And Do Not Define Suitable Curb Dimensions For A Real Project.
| Example | Dimensions | Calculation | Base Volume | With 10% Allowance |
|---|---|---|---|---|
| Small Straight Curb | 10 m × 150 mm × 300 mm | 10 × 0.15 × 0.30 | 0.450 m³ | 0.495 m³ |
| Long Straight Curb | 30 m × 150 mm × 300 mm | 30 × 0.15 × 0.30 | 1.350 m³ | 1.485 m³ |
| Heavy Curb Example | 20 m × 200 mm × 400 mm | 20 × 0.20 × 0.40 | 1.600 m³ | 1.760 m³ |
| Quarter-Circle Curb | 5 m Radius, 90°, 150 × 300 mm | Arc × 0.15 × 0.30 | 0.353 m³ | 0.388 m³ |
| Known Volume | 1.000 m³ | Direct Entry | 1.000 m³ | 1.100 m³ |
Concrete Volume Is Only One Part Of A Curb Budget. Preparation, Forming And Finishing Can Be Significant Cost Items.
Quick Answers About Curb Volume, Linear Metres, Curves, Waste And Concrete Bags.
Multiply Length In Metres By Width In Metres By Height In Metres For A Simple Rectangular Curb.
Multiply Curb Width By Height In Metres. The Cross-Sectional Area Is Also The Cubic Metres Required Per Linear Metre.
Add The Curb Cross-Sectional Area To The Gutter Cross-Sectional Area, Then Multiply By Total Length.
Calculate Arc Length From Radius And Angle, Then Multiply Arc Length By Curb Width And Height.
Arc Length = 2 × π × Radius × (Angle ÷ 360).
A Project-Specific Allowance Can Help Cover Small Variations In Forms, Excavation And Placement.
Yes. Enter The Yield Per Bag From The Exact Product Data Sheet. The Calculator Divides Required Volume By Yield And Rounds Up.
It Can Estimate Volume For A Rectangular Concrete Edge If You Know Length, Width And Height.
It Can Estimate Simple Geometry, But Civil Curbs May Use Authority-Specific Profiles, Slopes, Reinforcement And Drainage Details.
The Page Starts Clean So The Result Is Based Only On The Measurements And Rates You Enter.
It Multiplies Concrete Volume By The A$/m³ Rate You Enter. Other project costs may be separate.
The PDF Includes The Site Name, Curb Type, Measurements, Waste Allowance, Volume, Bag Estimate And Concrete-Only Cost.
Use Current Project Documents, Supplier Information And Safety Guidance Alongside Any Online Estimate.
Australian Industry Information And Technical Concrete Resources.
Visit CCAANational Information About Silica Hazards And Safe Work Requirements.
Read Silica GuidanceConfirm Mix, Delivered Rate, Minimum Load, Delivery Access And Order Increments.
Use The Actual Curb Profile, Dimensions, Reinforcement And Drainage Details.