Calculate concrete in cubic metres for Canberra and ACT projects using Australian units. Estimate slabs, round pads, strip footings and post holes, add an optional waste allowance, estimate 20 kg bags from the exact product yield, and enter your own local A$/m³ rate. Every numeric box shows a faint 0 only as a placeholder — the zero is not a real value.
The faint 0 inside each numeric field is a placeholder only. Click and type your number directly — typing 5 gives 5, not 05.
Your result appears after you press Calculate Concrete.
For a rectangular slab, multiply length in metres by width in metres by depth in metres. Divide millimetres by 1000 before using the depth.
See geometry, optional waste, order-friendly volume, bag quantity and your own local A$/m³ cost estimate.
Calculate the base quantity in Australian metric units.
Add only the allowance appropriate for the real site.
Use the exact manufacturer yield for packaged concrete.
Enter your current local rate rather than relying on stale pricing.
Save the estimate for quote comparison and planning.
Check current approvals and safety rules before construction.
Concrete quantity starts with volume. Whether you are planning a slab in Belconnen, a path in Tuggeranong, footings in Gungahlin or post holes elsewhere in the ACT, the maths depends on the actual shape and dimensions of the concrete. Canberra projects commonly use metres, millimetres and cubic metres, so the calculator keeps those units visible throughout.
The input boxes are intentionally empty. The faint 0 is only a visual placeholder and is not stored as a number. When a user types 5, the field contains 5 immediately instead of 05. Pressing Reset clears the field back to empty and the faint placeholder 0 returns.
Concrete m³ = Length (m) × Width (m) × Depth (mm ÷ 1000)A 6 m × 4 m slab at 100 mm thick contains 2.40 m³ before any contingency. If the design calls for 125 mm thickness, the same footprint contains 3.00 m³. Thickness has a direct effect on the quantity, so use the actual project dimension rather than a generic assumption.
| Example Project | Dimensions | Base Volume | With 5% | With 10% |
|---|---|---|---|---|
| Small Pad | 2 m × 2 m × 100 mm | 0.40 m³ | 0.42 m³ | 0.44 m³ |
| Patio Slab | 4 m × 4 m × 100 mm | 1.60 m³ | 1.68 m³ | 1.76 m³ |
| Garage Example | 6 m × 6 m × 100 mm | 3.60 m³ | 3.78 m³ | 3.96 m³ |
| Concrete Path | 12 m × 1 m × 100 mm | 1.20 m³ | 1.26 m³ | 1.32 m³ |
| Strip Footing | 20 m × 300 mm × 300 mm | 1.80 m³ | 1.89 m³ | 1.98 m³ |
A round pad is a cylinder. Divide diameter by two for radius, calculate π × radius² and multiply by depth in metres. The calculator can multiply the result for several identical pads.
Concrete m³ = π × Radius² × Depth × QuantityStrip footings use length × width × depth. Width and depth are entered in millimetres and converted to metres automatically. The correct footing dimensions must come from the project design; the calculator does not size foundations.
Post holes are cylindrical. Enter hole diameter, depth and quantity. An optional displacement percentage can provide a rough deduction for the post, although exact post volume is preferable where accuracy is important.
There is no single waste percentage that suits every job. Formed slabs over a carefully prepared base can be measured closely, while hand-dug trenches and holes may be less predictable. Spillage, low spots, excavation variation and supplier order increments can change the practical quantity.
Concrete pricing can vary with mix specification, strength, aggregate, additives, delivery distance, order size, pumping and supplier terms. Instead of hard-coding a price that can go stale, this calculator lets you enter the current A$/m³ rate from your own Canberra quote.
The cost result is concrete material only. Excavation, base preparation, reinforcement, formwork, pumping, labour, finishing, curing, saw cutting, testing and disposal can be separate items.
Bagged concrete can suit post holes, repairs and small pads. The bag estimate needs the finished product yield, not just the bag weight. Enter the yield from the exact product data sheet. If the field is left blank, the calculator intentionally shows no bag quantity.
ACT requirements depend on the type of building work. Many building projects require building approval, while some work may be exempt when the relevant conditions are met. Concrete quantity by itself does not tell you whether approval is needed, so check current ACT Planning information and confirm the project with the appropriate professional or certifier.
For approved work, ACT guidance includes requirements around certifiers, commencement and inspections. Reinforced concrete work can require inspection at the relevant stage before concrete is placed, depending on the project and building class.
The building-code pathway can depend on the timing of the project's building approval. The ACT currently has transition arrangements between NCC editions, so use the current ACT Government page and your certifier rather than relying on an old static article.
Concrete can contain crystalline silica. Cutting, grinding, drilling and chasing concrete can create respirable silica dust. WorkSafe ACT publishes current guidance and control requirements for ACT workplaces. Material estimating does not replace workplace risk controls.
This Canberra Concrete Calculator estimates material volume and optional concrete-only cost. It does not determine slab thickness, reinforcement, footing dimensions, concrete strength, exposure requirements, joints, drainage, structural performance, building approval or inspection requirements.
Continue planning with the Concrete Floor Calculator, Concrete Wall Calculator, Concrete Pier Foundation Calculator and Concrete Volume Calculator.
A material estimate gives you volume. ACT approvals, inspections, structural requirements and workplace safety remain separate parts of the project.
Use accurate metric measurements for the volume.
Check current ACT requirements and exemptions.
Use the code pathway applicable to the project.
Follow current ACT silica and workplace controls.
Answers about cubic metres, placeholder zeros, Canberra approvals, 20 kg bags, waste and local cost.
For a rectangular slab, multiply length in metres by width in metres by depth in metres. Divide millimetres by 1000 before using the depth.
The 0 is only a placeholder. It is not an entered value, so typing 5 gives 5 rather than 05.
Yes. Enter your own percentage or leave the field blank for exact geometry.
Yes, for volume estimating when the correct length, width and thickness are already known.
Yes. Use the Strip Footing option and enter length, width and depth.
Yes. Use hole diameter, depth and quantity.
Yes, if you enter the exact finished yield per bag from the manufacturer.
Yes. Enter your own A$/m³ rate from a current supplier quote.
Some ACT building work requires approval and some work may be exempt. Check current ACT Planning requirements for the specific project.
Use the strength and mix specification required by the project documents or qualified designer.
It is a quantity-planning tool only and does not replace design, approval, certification or inspection.
Yes. The PDF includes dimensions, volume, allowance, bag estimate when available and material-only cost.
Check current ACT Government information alongside the quantity estimate.
Current ACT information about building approvals, certifiers and commencement requirements.
View Building ApprovalsGuidance about approval exemptions and general conditions.
Check BA RequirementsACT information about current NCC commencement and transition arrangements.
View NCC InformationACT guidance for silica risks and workplace controls when working with concrete.
Read Silica Guidance