Estimate Concrete For A Retaining Wall Stem, Its Strip Footing, Or Both Together. Enter Your Actual Wall Dimensions, Add A Practical Waste Allowance, Estimate 20 Kg Bags And Build A Concrete-Only Budget Without Using A Fixed Structural Thickness Or Mix Assumption.
Use The Combined Option For A Straight Wall Stem Sitting On A Footing, Or Calculate Either Component Separately. If You Already Know The Required Concrete Volume, Use Known Volume To Add Waste, Bags And Cost.
Your Result Will Appear Here After You Press Calculate Retaining Wall Concrete.
The PDF Includes ConcreteCreek.com, Calculation Mode, Main Measurements, Waste Allowance, Wall And Footing Volumes, Rounded Order Volume, Bag Estimate And Concrete-Only Cost.
A Straight Concrete Retaining Wall Can Be Estimated As Two Rectangular Volumes: The Vertical Wall Stem And The Footing Below It. Calculate Each Component In Metres, Then Add Them Together.
The Tool Keeps Structural Design Separate From Quantity Estimating. You Supply The Dimensions; It Converts Those Dimensions Into Concrete Volume, Then Applies Your Own Waste, bag yield and price inputs.
Calculate The Vertical Concrete Section From Length, Height And Thickness.
Calculate The Base From Length, Footing Width And Footing Depth.
Combine The Wall And Footing Into A Single Cubic-Metre Quantity.
Add A Percentage For Real-World Differences In Formwork And Excavation.
Use Your Exact Product Yield To Estimate Whole Bags For Small Wall Work.
Use Your Own A$/m³ Supplier Rate Rather Than A Fixed Online Price.
A concrete retaining wall calculator is most useful when the wall geometry is already known from plans, engineering information or a clearly defined project scope. A retaining wall is not just a flat surface. A cast concrete wall commonly has a vertical stem and a footing below ground, and those two pieces can have very different dimensions. For quantity estimating, the safest approach is to calculate each concrete component separately and then add the volumes together.
The calculator on this page follows that method. It does not choose the correct wall height, stem thickness, footing width, footing depth or reinforcement. Those details depend on soil, retained height, surcharge loads, drainage, site constraints and structural requirements. Instead, the calculator takes the dimensions you already have and turns them into cubic metres, a waste-adjusted planning quantity, an optional 20 kg bag estimate and an editable concrete-only cost.
Volume (m³) = Wall Length (m) × Wall Height (m) × Wall Thickness (m)If wall thickness is shown in millimetres, divide by 1000 before multiplying. For example, 200 mm becomes 0.20 m. The formula is geometric only. A real wall may include steps, returns, columns, counterforts, thickened sections, construction joints or changes in thickness that should be measured as separate pieces.
Volume (m³) = Footing Length (m) × Footing Width (m) × Footing Depth (m)For a simple straight footing, the footing length can match the wall length. Do not assume that automatically if the footing changes around corners, steps down a slope or extends beyond the wall. Measure the actual footing run. Convert footing width and depth from millimetres to metres before calculating cubic metres.
Total Volume = Wall Stem Volume + Footing VolumeAfter combining the two volumes, you can apply a waste or contingency allowance. This is helpful because finished excavations and formwork are rarely perfectly identical to a drawing. The allowance should reflect the quality of site measurements rather than being treated as a universal rule.
| Millimetre Dimension | Metres | Use In Formula As |
|---|---|---|
| 100 mm | 0.100 m | 0.10 |
| 150 mm | 0.150 m | 0.15 |
| 200 mm | 0.200 m | 0.20 |
| 250 mm | 0.250 m | 0.25 |
| 300 mm | 0.300 m | 0.30 |
| 450 mm | 0.450 m | 0.45 |
| 600 mm | 0.600 m | 0.60 |
There is no single correct waste percentage for every retaining wall. A straight formed wall and neatly excavated footing can often be measured closely. Hand excavation, irregular ground, soft trench edges, stepped foundations, complicated corners and multiple pours can make the actual quantity less predictable. The calculator therefore leaves the waste entry at zero so you can choose a project-specific amount rather than inheriting an arbitrary default.
Sloping sites often produce retaining walls with stepped footings or changing wall heights. Do not average everything into one rectangle unless that approximation is acceptable for your purpose. A more reliable estimate divides the wall into sections. Measure each section length and its corresponding height, thickness and footing size, calculate its volume, then add all section totals together. The identical-section quantity field can help when several sections truly use the same dimensions.
A wall return adds concrete that may not be represented by the main straight length. The same applies to concrete pilasters, columns, buttresses or counterforts. These can be calculated as separate rectangular volumes and added to the main result. Be careful not to double-count overlap where two concrete shapes intersect. For irregular structural geometry, use dimensions from the construction documents rather than relying on a simplified sketch.
Bagged concrete can be practical for very small retaining wall repairs, isolated footing sections or locations where truck access is difficult. A substantial retaining wall can require a large number of bags, making mixing time, water control and placement continuity important considerations. The calculator does not assume how much concrete a 20 kg bag produces. Enter the yield stated on the exact product data sheet, then the tool divides the required volume by that yield and rounds up to whole bags.
Whole Bags = Rounded Concrete Volume ÷ Manufacturer Yield Per BagFor larger pours, compare the result with a ready-mix delivery plan using the Concrete Delivery Calculator. If you need to compare packaged-product coverage, use the Concrete Bag Coverage Calculator.
The concrete-only cost field multiplies the rounded order volume by the rate you enter. It intentionally does not use a national price because supplier rates, delivery charges, short-load fees, pumping, waiting time and regional conditions vary. For a broader estimate, compare the result with the Concrete Cost Calculator and the Concrete Material Cost Calculator.
Concrete is only one part of retaining wall cost. Excavation, spoil removal, drainage aggregate, drainage pipe, waterproofing or protective membranes, reinforcement, formwork, pumps, labour, finishing, backfill, engineering and permits can all affect the final project budget.
Steel reinforcement takes up some physical space inside concrete, but normal quantity estimates generally use the gross formed concrete volume rather than attempting to deduct each reinforcing bar. More importantly, the amount, size, spacing, cover and detailing of reinforcement are structural decisions. The concrete retaining wall calculator does not select reinforcement or verify structural adequacy.
A retaining wall holds back soil, so water management behind the wall can be critical. Drainage layers, pipes, outlets, waterproofing and suitable backfill are not represented by the concrete volume formula. If water pressure or soil conditions are important to the wall, follow the project documents and professional advice. A correct concrete quantity does not by itself make a retaining wall safe or durable.
For a formed wall stem, measure the internal dimensions of the completed formwork when possible. For the footing, check trench width and depth in several locations. Over-excavation can materially increase footing concrete, particularly on long runs. If the footing base is uneven, a single nominal depth may underestimate the real volume. Re-measuring after excavation and base preparation is one of the simplest ways to improve an order estimate.
The calculator measures quantity only. It does not decide MPa strength, slump, exposure classification, cement type, aggregate size or other mix properties. Use the specification shown in approved project documents or advice from the responsible engineer, builder or concrete supplier. For general industry information, the Cement Concrete & Aggregates Australia publishes concrete resources and technical information.
Cutting, grinding or drilling cured concrete can generate respirable crystalline silica. Planning concrete quantity is separate from controlling construction hazards. Review current workplace requirements and guidance such as Safe Work Australia silica guidance, and use appropriate controls for the actual task.
These Are Geometry Examples Only, Not Recommended Structural Sizes. Use The Dimensions Required For Your Actual Project.
| Example | Stem Dimensions | Footing Dimensions | Stem Volume | Footing Volume | Total |
|---|---|---|---|---|---|
| Short Wall Example | 5 m × 1 m × 150 mm | 5 m × 500 mm × 200 mm | 0.75 m³ | 0.50 m³ | 1.25 m³ |
| Garden Wall Example | 8 m × 1.2 m × 180 mm | 8 m × 600 mm × 250 mm | 1.73 m³ | 1.20 m³ | 2.93 m³ |
| Long Wall Example | 15 m × 1.5 m × 200 mm | 15 m × 700 mm × 300 mm | 4.50 m³ | 3.15 m³ | 7.65 m³ |
| Stem Only Example | 10 m × 1 m × 200 mm | — | 2.00 m³ | 0.00 m³ | 2.00 m³ |
Use Related ConcreteCreek.com Calculators To Check Volume, Bags, Materials, Delivery And Cost From Different Angles.
Common Questions About Wall Stem Volume, Footings, Bags, Waste, Cost And Quantity Planning.
Calculate the wall stem as length × height × thickness, calculate the footing as length × width × depth, then add the two cubic-metre volumes. Convert millimetres to metres before multiplying.
Yes. Choose Wall + Footing to calculate both parts, or use Footing Only if you want the foundation volume by itself.
Yes, but divide the stepped wall into sections with consistent dimensions. Calculate each section separately and add the results rather than forcing changing heights into one rectangle.
Enter the thickness required by your plans, engineering information or project specification. The calculator does not choose a structural retaining wall thickness.
Use the footing dimensions specified for the actual wall. Footing size is a structural design matter affected by wall height, soil and loads, so this calculator does not recommend a size.
There is no universal waste percentage. Choose an allowance that reflects excavation accuracy, formwork, wall complexity and site conditions. Rechecking the finished forms and footing excavation can improve the estimate.
Enter the actual yield per 20 kg bag from the product data sheet. The calculator divides the rounded required volume by that yield and rounds up to whole bags.
Yes. Enter your own concrete rate per cubic metre. The result is a concrete-only estimate and may not include delivery, pumping, short-load, waiting or other supplier charges.
No. Reinforcing steel, mesh, bars, chairs and installation are separate from the concrete quantity. Reinforcement design is outside the scope of this calculator.
No. The result is concrete volume only. Drainage pipe, drainage aggregate, membranes, waterproofing and backfill should be estimated separately.
You can use it for approximate straight segments of a curve, but a true curved wall needs geometry that reflects its actual length and cross-section. For important estimates, use dimensions from the project documentation.
The calculator intentionally starts every numeric entry at zero so your result is based only on measurements and rates you choose to enter, with no example quantity silently included.
The result remains hidden until Calculate Retaining Wall Concrete is pressed. This keeps the page clean and prevents example-looking numbers from being mistaken for a completed estimate.
Use Current Project Documents, Supplier Information And Appropriate Safety Guidance Alongside An Online Concrete Quantity Estimate.
Australian Concrete Industry Information And Technical Resources.
Visit CCAANational Information About Respirable Crystalline Silica And Workplace Controls.
Read Silica GuidanceUse The Exact Manufacturer Yield When Converting Cubic Metres Into Bag Quantities.
Confirm Structural Requirements, Mix Specification, Final Order Quantity And Delivery Conditions.