Compute How Much Concrete You Need For Slabs, Pads, Strip Footings, Round Columns Or Post Holes, And Multiple Concrete Sections. The Main Result Is Shown In Cubic Metres With A Cubic Yard Equivalent, Plus Waste Allowance, 20 Kg Bag Yield And Your Own A$/m³ Concrete Rate For A Clear Material And Cost Estimate.
Choose The Shape That Matches Your Project, Then Enter The Required Measurements. Every Numeric Entry Displays Zero As A Placeholder Without Forcing A Leading Zero While You Type. Results Stay Hidden Until You Press Compute Concrete.
Your Result Will Appear Here After You Press Compute Concrete.
The PDF Includes The Project Shape, Measurements, Cubic Metre Result, Cubic Yard Equivalent, Base Concrete Volume, Waste Allowance, 20 Kg Bag Estimate And Concrete-Only Cost.
Concrete Computation Starts By Converting Your Measurements Into A Three-Dimensional Volume. Rectangular Sections Use Length × Width × Depth, Round Sections Use The Cylinder Formula, And Multiple Sections Are Added Together. The Calculator Then Applies Your Waste Allowance And Shows Both m³ And yd³.
The Main Result Is Cubic Metres For Australian Concrete Planning, With The Cubic Yard Equivalent Included In The Result Description And PDF. Separate Figures Show Base Concrete, Added Waste, 20 Kg Bags And Concrete-Only Cost.
See The Computed Geometric Volume In Cubic Metres Before Waste Or Contingency Is Added.
Add A Percentage For Minor Measurement Differences, Spillage And Real Site Conditions.
Combine Base Volume And Waste Into One Final m³ Planning Quantity, With A yd³ Equivalent For Comparison.
Estimate Whole Bags Using The Yield From The Exact Product You Plan To Buy.
Multiply The Final Cubic Metre Quantity By Your Own Local A$/m³ Ready-Mix Rate, While The Estimator Also Keeps The yd³ Equivalent Available.
Save The Main Measurements, yd³ Result, m³ Equivalent And Cost Estimate With The Site Name For Reference.
A Concrete Computation Starts With Accurate Dimensions And The Correct Project Shape. For Rectangular Work, Enter Length And Width In Metres And Depth Or Thickness In Millimetres. For Round Work, Enter Diameter And Height Or Depth. The Calculator Converts Everything Into Cubic Metres And Also Displays The Equivalent Cubic Yards.
The Most Reliable Concrete Computation Separates Different Shapes And Depths. A Slab, Footing, Post Hole, Column, Edge Beam Or Other Section Can Use A Different Formula Or Thickness. Compute Each Section Separately, Add The Volumes Together, Then Apply A Practical Waste Allowance To The Combined Base Quantity.
Concrete Volume (m³) = Length (m) × Width (m) × Depth (m)
If A Slab Is 6 m Long, 4 m Wide And 100 mm Deep, Convert 100 mm To 0.10 m. The Base Volume Is 6 × 4 × 0.10 = 2.40 m³.
Cubic Yards (yd³) = Cubic Metres (m³) × 1.30795
Using The Same Example, 2.40 m³ × 1.30795 = 3.14 yd³ Before Waste. If You Add A 10% Allowance, The Planning Volume Becomes 2.64 m³, Which Is About 3.45 yd³. For Australian Ready-Mix Orders, Confirm The Final m³ Quantity With Your Supplier Even When You Use Cubic Yards For Comparison Or Project Planning.
A Straight Strip Footing Uses The Same Basic Rectangular Formula. Add The Total Footing Length In Metres, Then Convert Width And Depth From Millimetres To Metres Before Multiplying.
Footing Volume = Total Length × Width × Depth
A Round Column Is A Cylinder. Divide The Diameter By Two To Find The Radius, Square The Radius, Multiply By π, Then Multiply By Height Or Depth. If You Have More Than One Identical Column, Multiply By The Quantity.
Volume = π × Radius² × Height
For Repeated Identical Sections, Calculate The Volume Of One Section Then Multiply By The Number Of Sections. If You Already Know The m³ Volume Per Section, The Multiple Sections Option Lets You Enter That Directly And Add A Small Known Extra Volume If Needed.
| Concrete Section | Example Measurements | Base Formula | Example Volume |
|---|---|---|---|
| Rectangular Slab | 6 m × 4 m × 100 mm | 6 × 4 × 0.10 | 2.40 m³ |
| Strip Footing | 20 m × 400 mm × 300 mm | 20 × 0.40 × 0.30 | 2.40 m³ |
| Round Column | 400 mm Diameter × 2 m | π × 0.20² × 2 | 0.25 m³ |
| 4 Identical Pads | 0.50 m³ Each | 0.50 × 4 | 2.00 m³ |
Many Concrete Drawings And Site Measurements Use Millimetres For Depth, Width Or Diameter. Before You Use A Cubic-Metre Formula, Convert Millimetres To Metres By Dividing By 1000.
| Millimetres | Metres | Common Use |
|---|---|---|
| 75 mm | 0.075 m | Thin Concrete Layer Example |
| 100 mm | 0.100 m | Common Calculation Example |
| 125 mm | 0.125 m | Thicker Slab Example |
| 150 mm | 0.150 m | Heavy Slab Example |
| 300 mm | 0.300 m | Footing Depth Example |
| 400 mm | 0.400 m | Footing Width Or Diameter Example |
Waste Or Contingency Is Added After The Base Geometric Volume Is Calculated. It Provides A Small Buffer For Minor Measurement Variation, Uneven Excavation, Form Movement, Spillage Or Other Real Site Conditions.
Final Quantity = Base Volume × (1 + Waste Percentage ÷ 100)
Bag Quantity Depends On The Finished Yield Of The Exact Product. A 20 Kg Bag Weight Does Not Automatically Equal One Fixed Concrete Volume. Enter The Manufacturer-Stated Yield Per Bag, Then Divide The Final Concrete Quantity By That Yield And Round Up To A Whole Bag.
20 Kg Bags = Final Concrete Quantity ÷ Yield Per Bag
For Larger Projects, Concrete Is Often Ordered In Cubic Metres From A Ready-Mix Supplier. Use The Calculator Result As A Planning Figure, Then Discuss The Final Order Quantity, mix specification, site access and delivery conditions with the supplier.
The Calculator Multiplies The Final Cubic Metre Volume By The A$/m³ Rate You Enter. The Same Result Is Also Converted To Cubic Yards For Unit Comparison And Planning. The Cost Is Concrete-Only And Does Not Automatically Include Delivery, Short-Load Charges, Pumping, Labour, Reinforcement, Formwork, Excavation, Finishing Or Other Project Costs.
A Project Can Have Several Different Concrete depths and shapes. A slab may be 100 mm deep, while a strip footing is 300 mm deep. A thickened edge may use extra concrete around the perimeter. Calculating these separately makes the final quantity easier to check.
This Tool Does Not Decide Concrete Strength, Slab Thickness, Reinforcement, Footing Size, Column Size, joint layout, exposure classification or structural requirements. Those decisions must come from the appropriate project specification, plans or professional advice.
Keeping Each Step Separate Makes It Easier To Check Measurements, Base Volume, Waste, m³, yd³, Bags And Cost Before You Order.
Select Slab, Footing, Round Section Or Multiple Sections.
Add The Required Length, Width, Depth, Diameter And Quantity.
Calculate Each Section And Combine The Base m³ Quantity.
Add Waste And Review m³, yd³, Bags And Concrete-Only Cost.
These Examples Show How Different Concrete Shapes Convert Into Cubic Metres And Approximate Cubic Yards Before And After Waste.
| Project Example | Measurements | Base Volume | With 5% Waste | With 10% Waste |
|---|---|---|---|---|
| Small Pad | 2 m × 2 m × 100 mm | 0.40 m³ / 0.52 yd³ | 0.42 m³ / 0.55 yd³ | 0.44 m³ / 0.58 yd³ |
| Patio Slab | 5 m × 4 m × 100 mm | 2.00 m³ / 2.62 yd³ | 2.10 m³ / 2.75 yd³ | 2.20 m³ / 2.88 yd³ |
| Garage Slab | 6 m × 6 m × 100 mm | 3.60 m³ / 4.71 yd³ | 3.78 m³ / 4.94 yd³ | 3.96 m³ / 5.18 yd³ |
| Strip Footing | 20 m × 400 mm × 300 mm | 2.40 m³ / 3.14 yd³ | 2.52 m³ / 3.30 yd³ | 2.64 m³ / 3.45 yd³ |
| Workshop Slab | 8 m × 6 m × 125 mm | 6.00 m³ / 7.85 yd³ | 6.30 m³ / 8.24 yd³ | 6.60 m³ / 8.63 yd³ |
The Formula Is Straightforward, But Real Sites Can Use More Or Less Concrete Than A Perfect Geometric Shape.
Simple Answers About Concrete Volume, m³, yd³, Waste Allowance, 20 Kg Bags, Project Shapes And Concrete-Only Cost.
Select The Project Shape And Enter Its Dimensions. The Calculator Computes The Base Volume In m³, Adds Any Waste Allowance You Enter, And Shows The Final m³ Plus The yd³ Equivalent.
The Main Workflow Uses Metres And Millimetres And Reports Cubic Metres (m³). It Also Shows Cubic Yards (yd³) For Comparison; 1 m³ Is About 1.30795 yd³.
Divide By 1000. Therefore 100 mm = 0.10 m.
Yes. Use Strip Footing Mode And Enter The Total Length In Metres Plus Width And Depth In Millimetres.
Yes. Use Round Column Or Post Mode, Then Enter Diameter, Height Or Depth, And Quantity. The Calculator Uses The Cylinder Volume Formula.
There Is No Universal Percentage. The Appropriate Allowance Depends On Measurement Accuracy, excavation, formwork and site conditions.
Divide The Final Concrete Quantity By The Manufacturer-Stated Yield Per Bag And Round Up To A Whole Bag.
Each Numeric Field Is Empty But Displays A Zero Placeholder. This Keeps The Starting State Clear Without Forcing A Leading Zero When You Type A Number.
Yes. Enter Your Own A$/m³ Rate To Estimate Concrete Material Cost. Delivery, labour and other project costs are not automatically included.
The PDF Includes The Project Shape, Measurements, m³ Result, yd³ Equivalent, Base Volume, Waste Allowance, 20 Kg Bag Estimate And Concrete-Only Cost.
Check Current Product Information, 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, Mix Requirements, Delivery Conditions And Supplier Fees Before Ordering.