Work Out How Much Concrete You Need For A Project In Wollongong Or The Wider Illawarra Before You Order. Enter Metric Measurements, Add Your Own Waste Allowance, Estimate 20 Kg Premix Bags And Build A Concrete-Only Budget In Australian Dollars. The Calculator Covers Slabs, Round Pads, Strip Footings And Post Holes For Common Residential, Landscaping And DIY Planning Jobs.
Pick One Of The Four Options Below. Each Option Uses A Different Formula, But The Result Is Always Shown In Cubic Metres So You Can Compare The Quantity With Supplier Quotes Or Bagged Concrete.
Your Result Will Appear Here After You Press Calculate Concrete.
The PDF Includes The Site Name, Project Type, Measurements, Waste Allowance, Estimated Cubic Metres, Bag Count And Concrete-Only Cost.
This Simple Figure Shows Why Surface Area Alone Is Not Enough. A Concrete Quantity Needs Length, Width And Depth. The Depth Must Be Converted From Millimetres To Metres Before The Three Dimensions Are Multiplied.
The Tool Is Designed To Keep The Main Numbers Easy To See. It Separates The Exact Geometric Volume From The Waste Allowance, Then Shows An Order-Friendly Rounded Quantity, A Bag Estimate And An Editable Cost Estimate.
See The Base Quantity In Cubic Metres Before Any Extra Allowance Is Added.
Add A Percentage For Small Differences In Excavation, Forms And Real Site Conditions.
Estimate Whole Bags Using The Yield You Enter From The Exact Product Data Sheet.
Enter Your Own Local A$/m³ Rate Instead Of Relying On A Fixed National Price.
Save A Clear Estimate With The Site Name And Main Project Details For Easy Reference.
Use Metres, Millimetres, Cubic Metres And Australian Dollars Throughout The Wollongong Calculator.
A Concrete Estimate Starts With Volume. The Surface Area Of A Slab Is Helpful, But It Does Not Tell You How Much Concrete Is Needed Until The Thickness Is Included. In Australia, Concrete For Larger Jobs Is Commonly Discussed In Cubic Metres, So The Most Useful Calculation Is Length × Width × Depth With Every Measurement Converted To Metres.
The Calculation Is Easy When The Shape Is Regular. The More Important Part Is Measuring The Real Space Carefully. A Trench Can Become Wider Than Planned, A Base Can Have Low Spots, And Formwork Can Move Slightly. These Small Differences Are Why A Practical Concrete Estimate Often Includes A Waste Or Contingency Allowance Rather Than Ordering The Exact Drawing Volume With No Buffer.
Volume (m³) = Length (m) × Width (m) × Depth (m)
For Example, A Slab Measuring 6 Metres Long And 4 Metres Wide Has A Surface Area Of 24 Square Metres. If It Is 100 Millimetres Thick, The Thickness Becomes 0.10 Metres. The Base Volume Is 6 × 4 × 0.10 = 2.40 m³. If A 10% Allowance Is Added, The Planning Quantity Becomes 2.64 m³ Before Final Supplier Rounding.
Concrete Thickness Is Often Shown In Millimetres. Divide Millimetres By 1000 To Convert The Depth To Metres. A 100 mm Slab Is 0.10 m Deep. A 125 mm Slab Is 0.125 m Deep. A 150 mm Slab Is 0.15 m Deep.
| Concrete Thickness | Depth In Metres | Concrete Per 10 m² | 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 |
A Round Pad Uses The Area Of A Circle. Divide The Diameter By Two To Get The Radius, Then Multiply π × Radius² × Depth. If There Is More Than One Identical Pad, Multiply The Result By The Number Of Pads. The Calculator Does This Automatically.
For A Straight Strip Footing, Multiply The Total Length By The Width And The Depth. Width And Depth Are Often Easier To Enter In Millimetres On Site, So The Calculator Converts Them To Metres Before Calculating The Cubic Metres.
A Round Post Hole Is A Cylinder. The Formula Is π × Radius² × Depth. Multiply By The Number Of Holes. The Post Itself Takes Up Some Space, So A Small Displacement Adjustment Can Be Applied. For Critical Work, The Actual Post Size Should Be Calculated Rather Than Relying On A Simple Percentage.
There Is No Single Waste Percentage That Fits Every Job. Smooth Formwork Over A Carefully Prepared Base Can Be Measured Very Accurately. Hand-Dug Footings, Uneven Ground Or Several Small Sections Can Be Less Predictable. A 5% To 10% Planning Allowance Is Often Used As A Starting Point, But The Final Amount Should Match The Real Site Conditions.
Bagged Concrete Can Be Useful For Fence Posts, Repairs, Small Pads And Jobs Where A Ready-Mix Truck Is Not Practical. For A Larger Slab, The Number Of Bags Can Become Very High. The Calculator Uses The Bag Yield That You Enter, Because Different Products Can Produce Different Volumes Even When The Bag Weight Is The Same.
Number Of Bags = Required Concrete Volume ÷ Product Yield Per Bag
Always Check The Product Data Sheet Or Bag Instructions. Round Up To Whole Bags. Do Not Buy A Large Quantity Based Only On A Generic Online Yield If The Manufacturer Gives A Different Figure.
This Calculator Works Out Volume. It Does Not Decide The Correct Slab Thickness, Footing Size, Reinforcement, Joint Layout, Concrete Strength, Exposure Requirements, Slump, Curing Method Or Structural Design. Those Details Must Come From The Appropriate Plans, Specifications, Builder, Engineer Or Other Qualified Person Where Required.
The Concrete Calculator Wollongong is built for homeowners, renovators, landscapers, builders and anyone comparing concrete quantities around Wollongong and the Illawarra. The maths used to calculate concrete volume is simple, but the final order should still be checked against the real site, project drawings, local approvals and supplier requirements.
Start by measuring the actual concrete area in metres and millimetres. For a slab, multiply length by width by thickness. For a strip footing, use the full footing length, width and depth. For a round pad or post hole, use the circular volume formula. The calculator converts these measurements to cubic metres, adds the waste percentage you choose, estimates 20 kg bags from the yield you enter and lets you use a current local concrete rate rather than relying on a generic national price.
A driveway can involve more than calculating the private slab area. City of Wollongong states that Council approval is required before building a new driveway or replacing an existing driveway crossing. If the work crosses the public road reserve, footpath or verge, review the current Council requirements before construction starts.
Patios, garden paths, shed pads and other outdoor slabs are often easy to calculate because they can be split into rectangles. Measure each section separately, convert the selected thickness from millimetres to metres and add the volumes together. If the slab has steps, thickened edges, beams or irregular sections, calculate those components separately rather than assuming one average thickness across the whole project.
City of Wollongong also provides guidance for driveways, pathways and paving. Some hard surfaces within private property may be exempt development when the relevant NSW requirements are met, while work crossing public land can require Council approval. Check the current rules for the actual property and proposed work.
Small post holes, repairs and tiny pads can be practical with bagged concrete, while larger continuous pours can require a very large number of bags. This calculator does not assume one universal bag yield. Enter the cubic-metre yield printed on the specific product data sheet. For ready-mix, enter the current A$/m³ rate quoted for your Wollongong or Illawarra delivery instead of relying on an old online price.
Delivery access should be checked before the final quantity is booked. Wollongong includes dense urban streets, sloping blocks and properties close to the escarpment as well as more open suburban sites. A measured volume does not tell you whether a mixer truck can reach the discharge point, whether pumping will be needed or whether the access surface can support construction traffic. Discuss access, minimum loads, short-load fees, waiting time and placement method with the concrete supplier and contractor.
There is no single waste percentage that is correct for every Wollongong concrete project. Clean formwork over a well-prepared base can often be measured accurately. Hand-dug footings, irregular excavations, sloping ground and multiple small sections may be less predictable. The calculator therefore lets you enter your own percentage rather than forcing a default allowance.
Cubic metres answer the question “how much concrete?” MPa strength, exposure classification, reinforcement, cover, joints, curing and structural dimensions answer different design questions. The calculator does not select those requirements. Use the project drawings, specifications and advice from the appropriate builder, engineer or other qualified person when those decisions are required.
Concrete work can continue after the pour through cutting, drilling, grinding or demolition. SafeWork NSW publishes guidance on crystalline silica and controls for construction work involving concrete and masonry. Follow current work health and safety requirements for the actual task. A concrete quantity calculator cannot assess silica exposure or determine a safe work method.
For related planning, use the Concrete Cost Calculator, Concrete Foundation Wall Calculator, Concrete Pour Calculator and Concrete Truck Calculator. These tools help separate quantity, wall, pour and delivery calculations instead of forcing one calculator to answer every concrete planning question.
MPa Is A Different Part Of The Specification. It Describes Compressive Strength And Should Match The Requirements For The Project.
Seen In Some General Purpose Packaged Concrete Products, Depending On Product Instructions And Intended Use.
Frequently Encountered In Building Work, But It Is Not Automatically Correct For Every Slab Or Footing.
May Be Required Where Structural Or Exposure Conditions Call For A Higher Strength Mix.
Higher Strength Or Special Performance Concrete Should Be Ordered To The Exact Project Specification.
The Calculator Has An Editable A$/m³ Field Because Supplier Prices And Service Fees Can Change By Location, Mix, Order Size And Site Access.
These Examples Show The Maths Only. The Correct Structural Dimensions For A Real Project Must Come From The Project Requirements.
| Project Example | Dimensions | Calculation | Base Volume | With 10% Allowance |
|---|---|---|---|---|
| Small Slab | 3 m × 3 m × 100 mm | 3 × 3 × 0.10 | 0.90 m³ | 0.99 m³ |
| Garage-Size Example | 6 m × 6 m × 100 mm | 6 × 6 × 0.10 | 3.60 m³ | 3.96 m³ |
| Concrete Path | 12 m × 1 m × 100 mm | 12 × 1 × 0.10 | 1.20 m³ | 1.32 m³ |
| Strip Footing | 20 m × 300 mm × 300 mm | 20 × 0.30 × 0.30 | 1.80 m³ | 1.98 m³ |
| Round Pad | 3 m Diameter × 100 mm | π × 1.5² × 0.10 | 0.71 m³ | 0.78 m³ |
Simple Answers To Common Questions About Cubic Metres, Slab Thickness, Bags, Waste And Ready-Mix Ordering.
For A Rectangular Slab, Multiply Length In Metres By Width In Metres By Depth In Metres. Divide Millimetres By 1000 Before Using Them As Metres.
At 100 mm Thick, 1 m² Needs 0.10 m³. At 125 mm Thick It Needs 0.125 m³. At 150 mm Thick It Needs 0.15 m³.
There Is No Universal Percentage. A 5% To 10% Planning Allowance Is Often Used As A Starting Point, But The Right Amount Depends On The Accuracy Of Your Forms, Excavation And Site Measurements.
Use The Manufacturer-Stated Yield Per Bag. Divide 1 m³ By That Yield And Round Up. Different Products Can Have Different Yields, So Weight Alone Is Not Enough.
Bagged Concrete Can Be Convenient For Small Jobs. For Larger Continuous Pours, Ready-Mix Is Often More Practical Because Mixing Hundreds Of Bags Takes Considerable Time And Labour.
Not Always. Suppliers Can Charge For Delivery, Small Loads, Waiting Time, Regional Services, Testing Or Other Items. Request A Delivered Quote For Your Exact Project.
Yes For Volume Estimating If You Know The Correct Length, Width And Thickness. The Calculator Does Not Decide The Structural Thickness, Reinforcement Or Mix Specification.
The Result Appears Only After You Press Calculate Concrete So The Page Stays Clean And The Final Estimate Is Based On The Measurements You Have Chosen.
The PDF Includes The Site Name, Project Type, Key Measurements, Waste Allowance, Base Volume, Volume With Waste, Rounded Order Volume, Bag Estimate And Concrete-Only Cost.
Use The Strength And Mix Specification Required By The Plans, Engineer, Builder Or Other Project Documents. A Volume Calculator Cannot Select The Correct Structural Concrete Specification.
Use Current Supplier Information, Product Data Sheets And Australian Safety Guidance Alongside Any Online Concrete Estimate.
Current Council Information For New Or Replacement Driveway Crossings And Work Near The Road Reserve.
View Council GuidanceNSW Safety Information For Silica Risks Associated With Cutting, Grinding And Other Concrete Work.
Read SafeWork NSW GuidanceAustralian Concrete Industry Resources, Technical Guides, Datasheets And Reports.
Browse CCAA ResourcesConfirm The Final Quantity, Mix, Delivery Access, Minimum Load And Service Fees Before Ordering.