Work Out How Much Area Your Concrete Can Cover At A Chosen Depth. Enter Ready-Mix Volume In Cubic Metres Or The Number Of 20 Kg Premix Bags You Have, Then See The Estimated Coverage In Square Metres. You Can Also Start With A Known Area And Calculate The Concrete Volume Or Number Of Bags Required For The Job.
Select One Of The Four Options Below. You Can Find Coverage From A Known Concrete Quantity, Work Out Coverage From Bags, Convert A Known Area Into Cubic Metres, Or Estimate How Many Bags A Concrete Area May Need.
Your Result Will Appear Here After You Press Calculate Concrete Coverage.
The PDF Includes The Calculator Mode, Inputs, Coverage Or Required Quantity, Waste Allowance And Cost Information Entered In The Calculator.
The Same Cubic Metre Of Concrete Covers A Larger Area When The Slab Is Thin And A Smaller Area When The Slab Is Thick. Coverage Is Calculated By Dividing Concrete Volume By Depth In Metres.
Use The Calculator In Either Direction. Start With Concrete You Already Have And Find The Area It Can Cover, Or Start With A Known Area And Work Out How Much Concrete Or How Many Bags May Be Needed.
See How Many Square Metres A Known Concrete Volume Can Cover At Your Chosen Depth.
Convert A Known Surface Area And Depth Into The Cubic Metres Required For The Pour.
Use Manufacturer-Stated Bag Yield To Estimate Coverage Or The Number Of Bags Required.
Compare How Coverage Falls As Concrete Depth Increases From A Thin Layer To A Thicker Slab.
Use Your Own Ready-Mix Rate Or Bag Price To Build A Simple Concrete-Only Budget.
Save A Clear Coverage Or Quantity Estimate With The Site Name And Main Calculator Inputs.
Concrete Coverage Describes The Surface Area That A Known Volume Of Concrete Can Fill At A Chosen Depth. It Is Usually Shown In Square Metres. Coverage Is Useful When You Already Know How Much Ready-Mix Concrete Is Available, When You Have A Fixed Number Of Premix Bags, Or When You Want To Compare How Slab Thickness Changes The Area A Given Quantity Can Cover.
The Most Important Part Of A Coverage Calculation Is Depth. One Cubic Metre Of Concrete Is Always One Cubic Metre, But The Area It Covers Changes Depending On How Thickly It Is Placed. At 100 mm Deep, One Cubic Metre Covers 10 m². At 50 mm Deep, The Same Volume Covers 20 m². At 200 mm Deep, It Covers Only 5 m².
Coverage (m²) = Usable Concrete Volume (m³) ÷ Depth (m)
If You Have 2.5 m³ Of Concrete And Plan To Place It At 100 mm Deep, Convert 100 mm To 0.10 m. Without Any Loss Allowance, The Coverage Is 2.5 ÷ 0.10 = 25 m². If You Allow 5% For Waste Or Loss, The Usable Volume Becomes 2.375 m³ And The Estimated Coverage Falls To 23.75 m².
The Table Below Shows The Theoretical Surface Area Covered By 1 m³ Of Concrete At Different Uniform Depths. Real Site Coverage Can Be Lower If Excavation Is Uneven, Forms Are Not Exact Or Some Concrete Is Lost During Handling.
| Concrete Depth | Depth In Metres | Coverage From 1 m³ | Coverage From 5 m³ | Coverage From 10 m³ |
|---|---|---|---|---|
| 50 mm | 0.050 m | 20.00 m² | 100.00 m² | 200.00 m² |
| 75 mm | 0.075 m | 13.33 m² | 66.67 m² | 133.33 m² |
| 100 mm | 0.100 m | 10.00 m² | 50.00 m² | 100.00 m² |
| 125 mm | 0.125 m | 8.00 m² | 40.00 m² | 80.00 m² |
| 150 mm | 0.150 m | 6.67 m² | 33.33 m² | 66.67 m² |
| 200 mm | 0.200 m | 5.00 m² | 25.00 m² | 50.00 m² |
Bagged Concrete Coverage Depends On The Actual Yield Of The Product. A 20 Kg Bag Weight Does Not Tell You The Finished Concrete Volume By Itself. Use The Manufacturer-Stated Yield From The Bag Or Product Data Sheet. Multiply The Number Of Bags By The Yield Per Bag To Get Total Concrete Volume, Then Divide By The Depth In Metres.
Coverage (m²) = (Number Of Bags × Yield Per Bag In m³) ÷ Depth In Metres
The Table Below Uses A Simple Example Yield Of 0.010 m³ Per Bag Only To Show The Maths. Do Not Assume Every 20 Kg Product Has This Yield. Replace It With The Exact Figure For The Product You Plan To Buy.
| Concrete Depth | 1 Bag At 0.010 m³ | 10 Bags | 50 Bags | 100 Bags |
|---|---|---|---|---|
| 50 mm | 0.20 m² | 2.00 m² | 10.00 m² | 20.00 m² |
| 75 mm | 0.13 m² | 1.33 m² | 6.67 m² | 13.33 m² |
| 100 mm | 0.10 m² | 1.00 m² | 5.00 m² | 10.00 m² |
| 125 mm | 0.08 m² | 0.80 m² | 4.00 m² | 8.00 m² |
| 150 mm | 0.07 m² | 0.67 m² | 3.33 m² | 6.67 m² |
If You Already Know The Area Of The Slab Or Path, You Can Reverse The Coverage Calculation. Multiply Area In Square Metres By Concrete Depth In Metres. A 30 m² Area At 100 mm Deep Needs 3.00 m³ Before Waste.
Concrete Volume (m³) = Area (m²) × Depth (m)
A Waste Allowance Reduces The Area That A Fixed Quantity Can Reliably Cover. If You Have A Fixed 1 m³ Available And Allow 5% For Loss, Only 0.95 m³ Is Treated As Usable For Coverage. When You Start With A Known Area And Calculate Required Concrete, The Waste Percentage Works The Other Way: It Increases The Volume You Plan To Have Available.
The Calculator Assumes A Uniform Depth. Real Concrete Work Is Often Less Perfect. Excavations Can Have Low Spots, A Base Can Be Uneven, Formwork Can Bow, Thickened Edges May Use Extra Concrete And A Small Amount Can Remain In Tools Or Equipment. The More Irregular The Job, The More Important It Is To Measure Carefully Before Ordering.
Coverage Calculations Are Useful For Simple Flat Work Such As Paths, Patios And Pads When The Depth Is Known. They Can Also Help Compare Different Thicknesses. However, The Calculator Does Not Decide What Thickness Is Structurally Correct. Use The Project Specification, Plans Or Appropriate Professional Advice For That Decision.
This Tool Does Not Select Concrete Strength, Slab Thickness, Reinforcement, Joint Spacing, Exposure Classification, Base Preparation Or Structural Requirements. It Only Converts Between Area, Volume And Bag Quantities Using The Measurements And Yield You Enter.
These Simple Reference Values Show The Theoretical Coverage From 1 m³ Before Any Waste Or Site Variation Is Added.
One Cubic Metre Spread To 50 mm Deep Covers 20 Square Metres.
One Cubic Metre Spread To 100 mm Deep Covers 10 Square Metres.
One Cubic Metre Spread To 150 mm Deep Covers About 6.67 Square Metres.
One Cubic Metre Spread To 200 mm Deep Covers 5 Square Metres.
These Examples Show The Relationship Between Concrete Volume, Depth And Surface Coverage.
| Example | Concrete Quantity | Depth | Calculation | Theoretical Coverage |
|---|---|---|---|---|
| Small Ready-Mix Load | 1.00 m³ | 100 mm | 1.00 ÷ 0.10 | 10.00 m² |
| Patio Quantity | 2.50 m³ | 100 mm | 2.50 ÷ 0.10 | 25.00 m² |
| Thin Layer Example | 1.50 m³ | 75 mm | 1.50 ÷ 0.075 | 20.00 m² |
| Thicker Concrete | 3.00 m³ | 150 mm | 3.00 ÷ 0.15 | 20.00 m² |
| Heavy Section | 4.00 m³ | 200 mm | 4.00 ÷ 0.20 | 20.00 m² |
A Coverage Result Can Make It Easier To Compare The Practical Value Of A Ready-Mix Volume Or A Set Number Of Bags At The Depth Your Project Requires.
Simple Answers About Concrete Coverage, Depth, Cubic Metres And 20 Kg Bags.
At 100 mm Deep, 1 m³ Covers 10 m². At 50 mm Deep It Covers 20 m², And At 200 mm Deep It Covers 5 m² Before Any Waste Or Site Variation.
Divide Concrete Volume In Cubic Metres By The Depth In Metres. Convert Millimetres To Metres By Dividing By 1000 First.
It Depends On The Product Yield And The Concrete Depth. Multiply The Bag Yield In m³ By The Number Of Bags, Then Divide By The Depth In Metres.
Yes. A Fixed Volume Covers Less Surface Area As Depth Increases Because More Concrete Is Used Under Every Square Metre.
Yes. Use The Bags For Area Option. Enter The Area, Depth, Product Yield And Any Waste Allowance.
A Small Allowance Can Be Useful For Normal Site Variation, But It Should Not Replace Accurate Measurements. When Coverage Is Calculated From A Fixed Quantity, Waste Reduces The Usable Coverage.
Yes For Quantity Planning If You Know The Correct Concrete Depth. The Calculator Does Not Decide The Structural Thickness Or Reinforcement.
The Page Starts With Zero Values So Your Result Is Based Only On The Measurements, Yield And Prices You Choose To Enter.
The PDF Includes The Selected Calculator Mode, Main Inputs, Coverage Or Required Quantity, Waste Allowance And The Cost Information Entered.
m² Measures Surface Area. m³ Measures Concrete Volume. Coverage Connects The Two By Using The Concrete Depth.
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 Quantity, Mix Requirements, Delivery Conditions And Supplier Fees Before Ordering.