Concrete & construction
Concrete Wall Calculator
Works wall concrete, where formwork rather than concrete is the cost.
Result
Wall thickness, reinforcement and any required footing are structural decisions taken from the drawings. Formed walls also need bracing and a pour rate slow enough not to blow the forms, neither of which is a quantity question.
Get a Free Business AuditHow the calculation works
Wall length times height times thickness in cubic yards, with openings deducted. The concrete is a modest share of a wall's cost; the formwork, its bracing and the labour to erect and strip it are the larger part, and the form area rather than the concrete volume drives that.
What moves the number
- Wall length, height and thickness.
- Form area, which is both faces.
- Bracing required against the pour pressure.
- Reinforcement and any embedded items.
Where this one goes wrong
Formwork has to resist the pressure of wet concrete, which is considerable on a tall wall and increases with pour rate, and a form that moves or fails during a pour is both a safety matter and an expensive mess. Brace properly and pour at a controlled rate. The form area is both faces of the wall, which is the quantity to estimate labour and material against rather than the concrete volume.
Before you quote
- Estimate formwork from the area of both faces.
- Brace for the pressure of wet concrete at the pour rate.
- Place reinforcement and embedded items before pouring.
Where the rules come from
Questions
About this calculator
What drives the cost of a concrete wall?
Formwork, not concrete. The forms, their bracing and the labour to erect and strip them are the larger part, and the form area, meaning both faces of the wall, is the quantity that drives it rather than the volume.
Why does formwork fail?
Because wet concrete exerts considerable pressure, more on a tall wall and more at a fast pour rate. A form that moves or bursts during a pour is a safety matter and an expensive mess, which is why bracing and pour rate are planned.
Should openings be deducted?
From the concrete volume yes; from the formwork estimate only partly, since an opening needs its own boxing and the surrounding forms still have to be built. The two quantities behave differently.
The formula
cubic yards = area x thickness/12 / 27, plus waste
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How to use this calculator
- Wall length (ft) (ft). Enter your own figure; the page starts at 30 ft.
- Wall height (ft) (ft). Enter your own figure; the page starts at 8 ft.
- Wall thickness (in) (in). Enter your own figure; the page starts at 8 in.
- Waste allowance (%). Enter your own figure; the page starts at 8%.
- Concrete per cubic yard ($). Enter your own figure; the page starts at $165.
- Labour per sq ft ($). Enter your own figure; the page starts at $9.
The result updates as you type, so you can try a figure, see what it does to cubic yards to order, and change it back. Nothing you enter is sent anywhere or saved.
A worked example
These are the figures the calculator opens with. Every number in the results column below is produced by the same calculation the page runs, so you can follow it through before putting your own figures in.
What goes in
| Input | Value |
|---|---|
| Wall length (ft) | 30 ft |
| Wall height (ft) | 8 ft |
| Wall thickness (in) | 8 in |
| Waste allowance | 8% |
| Concrete per cubic yard | $165 |
| Labour per sq ft | $9 |
What comes out
| Result | Value |
|---|---|
| Cubic yards to order main result | 6.5 |
| Wall face area | 240.0 |
| Concrete cost | $1,073 |
| Estimated total | $3,233 |
| Cost per square foot | $13.47 |
That is 6.5 cubic yards over 240.0 square feet, about $3,233 all in, or $13.47 a square foot.
How sensitive the answer is
Holding everything else steady and changing only concrete per cubic yard, this is what happens to cubic yards to order. It is worth knowing which of your inputs the answer actually hinges on, and which barely move it.
| Concrete per cubic yard ($) | Cubic yards to order |
|---|---|
| $83 | 6.5 |
| $124 | 6.5 |
| $165 example above | 6.5 |
| $248 | 6.5 |
| $330 | 6.5 |
Every other input is held at the example value while this one changes, which is not how a real job behaves. Treat it as a guide to which number matters most, not as five separate quotes.
What each figure means
- Wall length (ft) (ft)
- Measured in ft, starting at 30 ft.
- Wall height (ft) (ft)
- Measured in ft, starting at 8 ft.
- Wall thickness (in) (in)
- Measured in in, between 0 and 120, starting at 8 in.
- Waste allowance (%)
- A percentage, between 0 and 40, starting at 8%.
- Concrete per cubic yard ($)
- A money amount, starting at $165.
- Labour per sq ft ($)
- A money amount, starting at $9.
What the results tell you
| Result | What it is |
|---|---|
| Cubic yards to order | The headline result. A decimal figure. |
| Wall face area | A decimal figure. |
| Concrete cost | A money figure. |
| Estimated total | A money figure. |
| Cost per square foot | A money figure. |
Order slightly more than this
Volume calculations assume a level, properly prepared base and exact dimensions. Sub-base variation, over-excavation and spillage all consume concrete, which is why most contractors add a margin. Running short mid-pour is far more expensive than a small overage.
Keep going
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