Calculate The Surface Area Of A Concrete Slab, Pad, Path Or Other Shape In Square Metres. Choose A Rectangle, Circle, Triangle Or Trapezoid, Enter Simple Metric Measurements, Then Add A Concrete Depth If You Also Want An Estimated Volume In Cubic Metres. The Tool Can Also Add Waste, Estimate 20 Kg Bags And Use Your Own Australian Dollar Concrete Rate.
Select The Shape That Best Matches Your Project. The Main Result Is Surface Area In Square Metres. If You Enter A Depth, The Calculator Also Shows Concrete Volume, Bags And An Estimated Concrete-Only Cost.
Your Result Will Appear Here After You Press Calculate Concrete Area.
The PDF Includes The Project Shape, Measurements, Surface Area, Concrete Depth, Waste Allowance, Volume, Bag Estimate And Concrete-Only Cost.
Area Measures The Surface In Square Metres. Concrete Volume Adds A Third Dimension: Depth. Once The Area Is Known, Multiply It By The Concrete Depth In Metres To Estimate Cubic Metres.
The Main Result Is Square Metres, But The Same Measurements Can Also Help With Concrete Volume, Bag Planning And Preliminary Cost Once A Depth Is Added.
See The Surface Area In Square Metres Before Any Concrete Depth Is Applied.
Add The Concrete Depth To Turn The Surface Area Into Cubic Metres.
Add A Percentage For Measurement Variation, Spillage And Real Site Conditions.
Estimate Whole Bags Using The Yield From The Exact Product You Plan To Buy.
Enter Your Own A$/m³ Rate To Build A Simple Concrete-Only Cost Estimate.
Save The Area And Volume Estimate For Your Project Records Or Supplier Discussion.
A Concrete Area Calculator Works Out The Size Of A Surface Before Depth Is Added. The Result Is Normally Shown In Square Metres (m²), Which Is Useful For Planning Slabs, Paths, Pads, Finishes, Sealers, Formwork Layouts And Other Concrete Work. If You Need To Order Concrete, Surface Area Is Only The First Step. You Also Need The Concrete Depth To Convert Square Metres Into Cubic Metres.
The Easiest Projects Are Rectangles And Squares. Other Sites May Include Curves, Triangles Or Tapered Sections. Instead Of Guessing, Divide The Site Into Simple Shapes, Calculate Each Area, Then Add The Results Together. This Approach Is Often Easier To Check And Reduces The Chance Of Missing Part Of The Project.
Area (m²) = Length (m) × Width (m)
A 6 Metre By 4 Metre Slab Has An Area Of 24 m². If The Concrete Is 100 mm Thick, Convert 100 mm To 0.10 m And Multiply 24 × 0.10 To Get 2.40 m³ Before Waste.
Area (m²) = π × Radius²
Measure The Full Diameter Across The Centre Of The Circle, Then Divide It By Two To Get The Radius. A 3 Metre Diameter Circle Has A Radius Of 1.5 Metres. Its Area Is About 7.07 m².
Area (m²) = ½ × Base × Perpendicular Height
The Height Must Be Measured At A Right Angle To The Base. Do Not Use A Sloping Side As The Height Unless It Is Actually Perpendicular To The Base.
Area (m²) = ½ × (Parallel Side A + Parallel Side B) × Perpendicular Height
This Shape Is Useful For Tapered Paths, Widening Slabs And Other Areas Where Two Opposite Sides Are Parallel But Different Lengths.
Once The Surface Area Is Known, Multiply By The Concrete Depth In Metres. This Is The Step That Changes m² Into m³. If Your Depth Is In Millimetres, Divide It By 1000 First.
| Concrete Depth | Depth In Metres | Volume For 10 m² | Volume For 25 m² | Volume For 50 m² |
|---|---|---|---|---|
| 75 mm | 0.075 m | 0.75 m³ | 1.88 m³ | 3.75 m³ |
| 100 mm | 0.100 m | 1.00 m³ | 2.50 m³ | 5.00 m³ |
| 125 mm | 0.125 m | 1.25 m³ | 3.13 m³ | 6.25 m³ |
| 150 mm | 0.150 m | 1.50 m³ | 3.75 m³ | 7.50 m³ |
Irregular Areas Are Usually Easier To Calculate When They Are Split Into Smaller Shapes. A Driveway Might Be One Rectangle Plus A Triangle At The Entrance. A Patio Could Be A Rectangle Plus A Circular Section. Calculate Each Part Separately, Then Add The Square Metres Together.
Waste Does Not Change The Physical Surface Area. It Changes The Amount Of Concrete You Plan To Have Available. That Is Why This Calculator First Works Out The Exact Area, Then Converts It To Volume, Then Applies The Waste Percentage To The Concrete Quantity.
You Cannot Work Out The Number Of 20 Kg Bags From Area Alone. Bag Quantity Depends On Volume, So The Depth Must Be Known. After The Volume Is Calculated, Divide It By The Manufacturer-Stated Yield Per Bag And Round Up To A Whole Bag.
The Cost Estimate Uses The Calculated Concrete Volume And The A$/m³ Rate You Enter. The Result Is A Concrete-Only Estimate. It Does Not Include Pump Hire, Labour, Reinforcement, Excavation, Formwork, Finishing, Delivery Fees Or Other Supplier Charges.
The Calculator Does Not Select Slab Thickness, Reinforcement, Concrete Strength, Joint Layout, Exposure Classification Or Structural Design. Those Decisions Must Match The Requirements For The Real Project.
These Units Answer Different Questions. Keeping Them Separate Makes Concrete Estimating Much Easier To Check.
Use Metres For The Main Horizontal Measurements Around The Concrete Area.
Square Metres Describe The Size Of The Top Surface Before Concrete Depth Is Added.
Depth Is Often Entered In Millimetres And Converted To Metres For The Volume Formula.
Cubic Metres Describe The Three-Dimensional Quantity Used For Concrete Ordering.
These Examples Show How Common Shapes Change From Metres To Square Metres, Then To Cubic Metres At A 100 mm Concrete Depth.
| Shape | Measurements | Area Formula | Area | Volume At 100 mm |
|---|---|---|---|---|
| Rectangle | 6 m × 4 m | 6 × 4 | 24.00 m² | 2.40 m³ |
| Square | 5 m × 5 m | 5 × 5 | 25.00 m² | 2.50 m³ |
| Circle | 3 m Diameter | π × 1.5² | 7.07 m² | 0.71 m³ |
| Triangle | 5 m Base × 4 m Height | ½ × 5 × 4 | 10.00 m² | 1.00 m³ |
| Trapezoid | 5 m + 3 m, Height 4 m | ½ × (5 + 3) × 4 | 16.00 m² | 1.60 m³ |
Area Alone Does Not Control Concrete Quantity. Depth, Thickened Sections, Beams, Edges And Site Conditions Can Change The Final Volume.
Simple Answers About Square Metres, Concrete Depth, Volume And Irregular Shapes.
For A Rectangular Slab, Multiply Length By Width. For Example, 6 m × 4 m = 24 m².
Multiply The Area In m² By The Concrete Depth In Metres. A 24 m² Area At 100 mm Deep Uses 24 × 0.10 = 2.40 m³ Before Waste.
Yes. Enter The Diameter. The Calculator Divides It By Two To Find The Radius, Then Uses π × Radius².
Split The Site Into Simple Shapes Such As Rectangles, Triangles And Circles. Calculate Each Part Separately And Add The Results.
No. Waste Does Not Change The Physical Area. It Is Applied To The Concrete Volume To Provide A Planning Allowance.
You Need The Concrete Depth As Well As The Area. Area × Depth Gives Volume. Divide That Volume By The Product Yield Per Bag.
Yes For Area And Volume Estimating If The Shape And Measurements Are Entered Correctly. Structural Requirements Still Need To Come From The Project Design.
m² Measures Surface Area. m³ Measures Volume. Concrete Ordering Usually Needs Volume Because The Slab Has Length, Width And Depth.
The Result Appears After You Press Calculate Concrete Area So The Final Result Matches The Measurements And Shape You Chose.
The PDF Includes The Shape, Measurements, Area, Depth, Waste Percentage, Concrete Volume, Bag Estimate And Concrete-Only Cost.
Check Current Product Information, Concrete Supplier Advice And Australian Safety Guidance Before Ordering Or Carrying Out Concrete Work.
Australian Industry Information And Technical Resources For Concrete Construction.
Visit CCAANational Safety Information About Silica And Concrete-Related Work Hazards.
Read Silica GuidanceExample Australian Product Information For Packaged General Purpose Concrete.
View Product InformationConfirm Final m³ Quantity, Delivery Conditions, Mix Requirements And Supplier Fees Before Ordering.