Work Out How Many Concrete Bags You Need From The Actual Product Yield, Convert Bag Yield Into Litres And Cubic Metres, Estimate Total Mixed Volume, Add A Waste Allowance And Check The Approximate Cost Before You Buy. The Concrete Bag Yield Calculator Uses The Yield You Enter From The Manufacturer Rather Than Assuming That Every 20 Kg, 25 Kg Or 30 Kg Bag Produces The Same Amount Of Concrete.
Select A Calculation Mode Below. For The Most Accurate Result, Enter The Mixed Concrete Yield Printed On The Exact Bag, Technical Data Sheet Or Manufacturer Product Page.
Your Result Will Appear Here After You Press Calculate Bag Yield.
The PDF Records The Calculation Mode, Yield Inputs, Bag Quantity, Volume And Cost Figures Used In Your Estimate.
Concrete Bag Yield Is The Mixed Volume Produced By One Bag. Once The Yield Is Known, The Calculation Is Simple: Multiply The Yield Per Bag By The Number Of Bags, Or Divide The Project Volume By The Yield Per Bag To Find How Many Bags Are Required.
The Calculator Keeps Product Yield Separate From Bag Weight So You Can Use Real Manufacturer Information And See The Numbers That Matter For Buying, mixing and budgeting packaged concrete.
Estimate Whole Bags Needed For A Target Concrete Volume And Optional Waste Allowance.
See The Combined Mixed Yield From Any Number Of Bags Using The Product Yield You Enter.
Convert Packaged Concrete Output Into Cubic Metres For Easier Comparison With Project Volumes.
Estimate Purchase Cost From The Whole-Bag Quantity And Your Current Price Per Bag.
Compare Two Products By Yield, Bags Needed And Estimated Cost For The Same Volume.
Save A Clean ConcreteCreek.com Calculation Summary For Reference Before Shopping.
A Concrete Bag Yield Calculator Helps Convert Packaged Dry Concrete Into The Mixed Volume You Actually Need For A Project. This Matters Because A Bag Is Usually Sold By Weight, While A Slab, Footing, Post Hole Or Repair Is Planned By Volume. Those Two Numbers Are Related, But They Are Not Interchangeable. A 20 Kg Bag Does Not Automatically Mean A Fixed Number Of Litres Of Finished Concrete Across Every Brand And Product.
The Most Reliable Starting Point Is The Manufacturer-Stated Yield. This May Be Shown In Litres, Cubic Metres, Or As An Approximate Coverage Statement On The Bag Or Technical Data Sheet. Enter That Yield Into The Calculator, Then Tell The Tool Either How Much Concrete You Need Or How Many Bags You Plan To Mix. The Calculator handles the unit conversion and rounds bag requirements up to whole bags.
If You First Need To Work Out The Geometric Volume Of A Slab, Pad, Footing Or Post Hole, Use The Concrete Calculator Australia Before Returning To This Page. Once You Have The Required Cubic Metres, The Concrete Bag Yield Calculator Can Translate That Volume Into A Packaged Concrete Quantity.
Total Yield (L) = Number Of Bags × Manufacturer Yield Per Bag (L)For Example, If One Product States That Each Bag Produces 10 Litres Of Mixed Concrete, 25 Bags Produce An Estimated 250 Litres. Because 1,000 Litres Equals 1 Cubic Metre, 250 Litres Equals 0.25 m³.
Bags = Required Volume (m³) × 1,000 ÷ Yield Per Bag (L)If Your Project Needs 0.60 m³ And The Product Yield Is 10 L Per Bag, The Base Calculation Is 0.60 × 1,000 ÷ 10 = 60 Bags. If You Add A 5% Planning Allowance, The Required Volume Becomes 0.63 m³, Which Is 630 L, So The Calculator Returns 63 Whole Bags.
Bag Weight Describes The Mass Of Dry Material In The Package. Yield Describes The Approximate Volume Of Mixed Concrete Produced When The Product Is Prepared According To Its Instructions. Product Formulation, Aggregate Grading, Cement Content And Recommended Water Can Differ, So Two Bags With The Same Nominal Weight Can Have Different Mixed Yields.
That Is Why This Concrete Bag Yield Calculator Does Not Hard-Code A Universal Rule Such As “One 20 Kg Bag Always Equals 0.01 m³.” A Generic Estimate Can Be Useful For Rough Planning, But Buying Decisions Should Be Based On The Exact Product Information. The Master ConcreteCreek.com calculator approach uses editable product yield for the same reason: the user can replace an example with the data printed by the manufacturer.
Packaged Concrete Yield Is Often Easier To Understand In Litres, While Larger Project quantities are usually handled in cubic metres. The conversion is exact: 1,000 L = 1 m³. Divide litres by 1,000 to get cubic metres, or multiply cubic metres by 1,000 to get litres.
| Total Mixed Yield | Litres | Cubic Metres | Cubic Feet Approx. | Cubic Yards Approx. |
|---|---|---|---|---|
| Small Repair Quantity | 50 L | 0.050 m³ | 1.77 ft³ | 0.065 yd³ |
| Small Pad Quantity | 100 L | 0.100 m³ | 3.53 ft³ | 0.131 yd³ |
| Medium Bagged Job | 250 L | 0.250 m³ | 8.83 ft³ | 0.327 yd³ |
| Larger Bagged Job | 500 L | 0.500 m³ | 17.66 ft³ | 0.654 yd³ |
| One Cubic Metre | 1,000 L | 1.000 m³ | 35.31 ft³ | 1.308 yd³ |
The Answer Depends On Yield Per Bag. If A Product Yields 8 L, One Cubic Metre Requires 125 Bags Before Any Extra Allowance. At 10 L Per Bag, The Maths Is 100 Bags. At 12 L Per Bag, 1,000 ÷ 12 = 83.34, So You Must Round Up To 84 Bags. At 15 L Per Bag, The Result Is About 67 Bags.
| Example Yield Per Bag | Bags For 0.25 m³ | Bags For 0.50 m³ | Bags For 1.00 m³ | Bags For 2.00 m³ |
|---|---|---|---|---|
| 8 L | 32 | 63 | 125 | 250 |
| 9 L | 28 | 56 | 112 | 223 |
| 10 L | 25 | 50 | 100 | 200 |
| 12 L | 21 | 42 | 84 | 167 |
| 15 L | 17 | 34 | 67 | 134 |
These Rows Are Maths Examples, Not Product Claims. If You Are Comparing Products, Enter Each Product's Actual Stated Yield In The Compare Yields Mode. You Can Then Compare The Whole-Bag Quantity And Approximate Purchase Cost For The Same Project volume.
A Pure Geometry Calculation Assumes Every Litre Of Mixed Concrete Goes Into The Intended Space. Real Work Can Include Material Left In The Mixer, Wheelbarrow Or Bucket, Minor Spillage, Uneven Excavation, Formwork variation and small measurement differences. Adding a modest contingency can reduce the chance of running short at the end.
The right allowance depends on the job. Tight, well measured formwork may need very little extra. Hand-dug post holes or rough excavations can be less predictable. The calculator lets you set your own percentage rather than forcing one number on every project. It is still good practice to remeasure the actual forms or holes before purchasing a large quantity of bags.
Price per bag alone can be misleading. A cheaper bag can cost more for the finished volume if it produces less concrete. The useful comparison is the cost of the volume you receive. In Compare Yields mode, enter the manufacturer yield and price for Product A and Product B. The calculator estimates how many whole bags each option needs for the same target volume and shows the approximate purchase cost.
Cost Per m³ = Price Per Bag ÷ Yield Per Bag (m³)For example, a bag costing A$12.50 with a 10 L yield has a simple material rate of A$1.25 per litre, or A$1,250 per m³ before bag rounding, waste and any delivery or collection costs. A bag costing A$14.50 with a 12 L yield works out to about A$1.21 per litre, or roughly A$1,208 per m³ on the same simple basis. The higher sticker price can therefore be the lower cost per finished volume.
Bagged concrete is convenient for small repairs, fence posts, isolated pads and locations where a ready-mix truck cannot easily reach. As volume rises, the number of bags, mixing time, water measuring, handling and labour rise quickly. Before committing to hundreds of bags, compare the total packaged concrete cost with a delivered ready-mix quote and consider the practical time needed to mix and place the concrete continuously.
For larger jobs, use the Concrete Cost Calculator to compare broader material budgeting, and check the Concrete Bags To Cubic Metres Guide when you want a quick unit-focused reference. If you are estimating a slab first, the Concrete Slab Calculator can help determine the starting volume before converting that volume into bags.
Manufacturer yield assumes the product is mixed according to the stated instructions. Adding too much water to make concrete easier to place is not a safe way to create more usable concrete. Excess water can change consistency and may affect strength, finish, shrinkage and durability. Follow the product directions rather than trying to stretch a bag beyond its intended yield.
Consistency between batches also matters. When many bags are mixed separately, use consistent measuring tools and a repeatable mixing process. This helps reduce variation in workability and finished results. For structural or regulated work, follow the project specification and product requirements rather than relying on an online calculator as a design tool.
The Tool Calculates Quantity, Yield And Simple Material Cost. It Does Not Select The Correct Concrete Strength, Slab Thickness, Reinforcement, Footing Size, Joint Layout, Exposure Classification, Curing Method Or Structural Design. Those Decisions Need To Come From The Appropriate Plans, Specifications, Building Requirements, Engineer, Builder Or Qualified Professional Where Required.
When Reading A Concrete Bag, Three Numbers Can Easily Be Confused: Bag Weight, Mixed Yield And Coverage. Bag Weight Is The Mass Of The Dry Mix. Mixed Yield Is The Volume Of Concrete Produced After The Recommended Water Is Added And The Product Is Mixed. Coverage Usually Describes How Much Area The Product Can Fill At A Particular Thickness. A Concrete Bag Yield Calculator Needs The Mixed Yield Because That Is The Number That Connects A Bag To A Three-Dimensional Project Volume.
Coverage Can Still Be Useful As A Cross-Check. If A Manufacturer Says A Product Covers A Certain Area At A Given Thickness, That Statement Can Be Converted Back Into Volume By Multiplying Area By Thickness. However, The Direct Yield Figure Is Usually Simpler To Use. If Product Information Is Unclear, Do Not Assume That A Weight-Based Online Table Is More Reliable Than The Exact Manufacturer Instructions.
Fence Posts And Small Foundations Are Common Reasons To Buy Packaged Concrete. A Round Post Hole Is A Cylinder, So Its Volume Is Based On Diameter And Depth. If Several Holes Are The Same Size, Multiply The Single-Hole Volume By The Number Of Holes. The Post Itself Takes Up Some Space, But The Amount Depends On The Post Cross-Section And How It Is positioned. For a close estimate, calculate actual displacement rather than applying a generic percentage.
Once The Combined Post-Hole Volume Is Known, Enter It In Bags Needed Mode. This Is More Accurate Than Using A Rule Such As “Two Bags Per Post,” Because Hole Diameter, Depth And Product Yield Can All Vary. Deep Or Oversized Holes Can Use Significantly More Concrete Than A simple bag-per-post rule suggests.
For A Rectangular Slab, Volume Equals Length × Width × Depth. Thickness Has A Large Effect On Bag Count. A 10 m² Area At 100 mm Thick Is 1.00 m³, While The Same 10 m² Area At 150 mm Thick Is 1.50 m³. At An Example Yield Of 10 L Per Bag, That Difference Is 50 Bags Before Any Waste Allowance. This Is Why The Thickness Should Never Be Estimated Casually.
| Area | Thickness | Concrete Volume | Bags At 10 L Yield | Bags At 12 L Yield |
|---|---|---|---|---|
| 5 m² | 75 mm | 0.375 m³ | 38 | 32 |
| 5 m² | 100 mm | 0.500 m³ | 50 | 42 |
| 10 m² | 100 mm | 1.000 m³ | 100 | 84 |
| 10 m² | 125 mm | 1.250 m³ | 125 | 105 |
| 10 m² | 150 mm | 1.500 m³ | 150 | 125 |
Bag Calculations Must Usually Be Rounded Up. That Makes Small Projects Look Slightly Less Efficient Because One Extra Bag Can represent a meaningful percentage of the total. If a repair mathematically needs 3.1 bags, the purchase quantity is 4 bags. If a slab needs 103.1 bags, the purchase quantity is 104. The calculator uses whole-bag rounding so the result reflects how packaged concrete is normally purchased.
Whole-Bag Rounding Is Different From A Waste Allowance. Waste Is An Intentional Extra Volume Added Before Calculating Bags. Rounding Is Simply The Final Step Needed Because Partial Sealed Bags Are Not Normally Sold. Keeping Those Two Steps Separate Makes The Estimate Easier To Audit.
The Right Contingency Depends On Project Size And Uncertainty. For A Very Small Repair, One Extra Bag May Be A Large Percentage Of The Job But Can Prevent A Disruptive Shortage. For A Larger Bagged Pour, A Percentage-Based Allowance Can Be Easier To Apply consistently. Consider whether unopened bags can be returned, how far the store is from the site, whether the pour must be continuous and how accurately the space has been measured.
Do Not Use Extra Bags As A Substitute For Correct Measurement. Buying 10% More Than A Bad Volume Estimate Does Not Guarantee Enough Concrete. The Best Sequence Is Accurate Measurement First, Then A Reasonable contingency, then whole-bag rounding.
ConcreteCreek.com Uses Metric Units On This Page Because Litres And Cubic Metres Fit Australian Packaged Concrete planning well. If your plans or product information use cubic feet or cubic yards, convert the volume before comparing it with litre-based bag yield. The Concrete Bags To Cubic Feet Guide can help when working with imperial volume references.
| Volume Reference | Litres Approx. | Cubic Metres Approx. | Cubic Feet Approx. | Cubic Yards Approx. |
|---|---|---|---|---|
| 10 Litres | 10 L | 0.010 m³ | 0.353 ft³ | 0.013 yd³ |
| 25 Litres | 25 L | 0.025 m³ | 0.883 ft³ | 0.033 yd³ |
| 1 Cubic Foot | 28.32 L | 0.0283 m³ | 1.000 ft³ | 0.037 yd³ |
| 100 Litres | 100 L | 0.100 m³ | 3.531 ft³ | 0.131 yd³ |
| 1 Cubic Yard | 764.55 L | 0.7646 m³ | 27.000 ft³ | 1.000 yd³ |
This Tool Is Especially Helpful When A Job Is Too Small For A Convenient Ready-Mix Delivery But Too Large To Guess By Eye. Typical Uses Include Fence Posts, mailbox or sign posts, steps, small equipment pads, garden edging, small footings, repair patches, shed slabs, kerb repairs and isolated sections where packaged concrete is easier to transport.
For A Large Structural Pour, The Calculator Is Still Useful As A Comparison Tool, But It Should Not Be The Only Planning step. Large volumes can require many hundreds of bags, substantial mixing capacity and careful placement timing. Compare the bagged option with supplier quotes, labour requirements and the practical ability to place the concrete before earlier batches begin to set.
The Numbers Below Show Why Product Yield Matters. They Are Calculation Examples Only—always replace them with the yield printed for your exact product.
A Lower Yield Means More Bags Are Needed For The Same Finished Volume.
Easy Maths Example Often Used For Planning, But Not A Universal Product Rule.
1,000 ÷ 12 Is 83.34, So The Purchase Quantity Rounds Up To 84 Bags.
A Higher Yield Reduces The Whole-Bag Count, Subject To The Actual Product Data.
Each Example Uses A Stated Yield For Demonstration. Replace The Example Yield With The Manufacturer Information For The Concrete You Plan To Buy.
| Project Example | Required Volume | Yield Per Bag | Waste | Whole Bags | Total Nominal Yield |
|---|---|---|---|---|---|
| Small Repair | 0.08 m³ | 10 L | 5% | 9 | 90 L |
| Fence Post Batch | 0.18 m³ | 10 L | 5% | 19 | 190 L |
| Small Pad | 0.30 m³ | 12 L | 5% | 27 | 324 L |
| Half Cubic Metre | 0.50 m³ | 10 L | 5% | 53 | 530 L |
| One Cubic Metre | 1.00 m³ | 10 L | 5% | 105 | 1,050 L |
The Calculator Covers Bag Purchase Cost, But A Complete Project Budget Can Include More Than The Shelf Price Of The Concrete Mix.
Answers To Common Questions About Bag Yield, Litres, Cubic Metres, Whole-Bag Rounding, Waste And Packaged Concrete Cost.
Concrete Bag Yield Is The Approximate Volume Of Mixed Concrete Produced By One Bag When It Is Prepared According To The Manufacturer Instructions. It May Be Stated In Litres, Cubic Metres Or Another Volume Unit.
Multiply The Number Of Bags By The Manufacturer-Stated Yield Per Bag. If Each Bag Yields 10 L, 40 Bags Produce A Nominal 400 L, Which Is 0.40 m³.
Divide 1,000 L By The Yield Per Bag And Round Up. At 10 L Per Bag The Maths Is 100 Bags. At 12 L Per Bag It Is 83.34, So You Would Need 84 Whole Bags Before Any Extra Allowance.
No. Bag Weight Alone Does Not Guarantee The Same Finished Yield Across Different Products. Use The Specific Yield Stated On The Bag Or Manufacturer Data Sheet.
A Small Contingency Can Be Useful Where Measurements, Excavation Or Handling Are Not Perfect. The Appropriate Percentage Depends On The Job. Recheck The Real Project Dimensions Before Buying.
Concrete Mix Is Usually Purchased As Complete Bags. If The Maths Produces 52.1 Bags, You Cannot Normally Buy 0.1 Of A Sealed Bag, So The Purchase Estimate Rounds Up To 53.
Yes. Use Compare Yields Mode And Enter The Yield And Price Of Each Product. The Calculator Shows The Whole Bags And Approximate Cost Needed For The Same Target Volume.
Divide Litres By 1,000. For Example, 500 L = 0.50 m³ And 1,250 L = 1.25 m³.
Yes, If You Already Know The Total Concrete Volume Required For The Holes. For Calculating The Hole Volume First, Use A Post Hole Or General Concrete Volume Calculator And Then Convert The Result Into Bags.
Yes For Bag Quantity Once The Slab Volume Is Known. Calculate Length × Width × Depth First, Then Enter The Cubic Metres Into Bags Needed Mode.
Do Not Add Extra Water Simply To Stretch The Volume. Follow The Product Mixing Instructions. Excess Water Can Change Concrete Performance And Finished Quality.
It Can Be Used, But The Bag Count And Mixing Labour Increase Quickly. For Larger Continuous Pours, Compare The Total Packaged Concrete Cost And Workload With A Delivered Ready-Mix Quote.
Check Current Manufacturer Data And Safety Guidance Alongside Any Online Concrete Bag Yield Estimate.
Example Australian Manufacturer Information For Packaged Concrete Mix.
View Product InformationAustralian Concrete Industry Information And Technical Resources.
Visit CCAANational Guidance About Silica Hazards And Safe Work Controls.
Read Silica GuidanceUse The Exact Yield, Water Addition, Application Limits And Safety Instructions For The Bag You Purchase.