Concrete Wall Calculator
A concrete wall calculator multiplies length × height × thickness ÷ 27 for cubic yards: a 20 ft wall, 4 ft tall and 8 in thick, needs 1.98 yd³ of concrete.
How much concrete do I need for a wall?
This concrete wall calculator finds the volume of a formed, poured wall with one formula: cubic yards = length × height × (thickness in inches ÷ 12) ÷ 27. A wall 20 ft long, 4 ft tall, and 8 inches thick needs 1.98 cubic yards, or 2.17 cubic yards with the 10% waste box ticked. At $150 a yard that is $296.30, or $325.93 with waste.
Enter the wall length in the Length field, the wall height in the Width field, and the thickness in inches in the Depth field, then your ready-mix price per cubic yard.
The formula in plain words
A wall is just a slab stood on its edge. The calculator:
- Converts thickness to feet: 8 in ÷ 12 = 0.667 ft.
- Multiplies length × height × thickness for cubic feet.
- Divides by 27 for cubic yards.
- Adds 10% if the waste box is ticked.
- Multiplies by your price per yard.
The footing under the wall is a separate pour with a different shape. Figure it with the concrete footing calculator.
Worked examples
- Default: 20 ft long × 4 ft tall × 8 in thick, $150/yd³
- Cubic feet: 20 × 4 × 0.667 = 53.33 ft³
- Cubic yards: 53.33 ÷ 27 = 1.98 yd³, costing $296.30
- With 10% waste: 2.17 yd³, costing $325.93
- Basement wall: 36 ft × 8 ft × 8 in, $150/yd³
- Cubic feet: 36 × 8 × 0.667 = 192 ft³
- Cubic yards: 192 ÷ 27 = 7.11 yd³, costing $1,066.67
- With 10% waste: 7.82 yd³, costing $1,173.33
Ready-mix trucks commonly carry somewhere around 8 to 10 cubic yards, so example 2 fits in one truck. Confirm the size with your supplier.
Cubic yards per 10 ft of wall
| Wall height | 6 in thick | 8 in thick | 10 in thick |
|---|---|---|---|
| 4 ft | 0.74 | 0.99 | 1.23 |
| 8 ft | 1.48 | 1.98 | 2.47 |
| 9 ft | 1.67 | 2.22 | 2.78 |
Multiply by your wall length ÷ 10. A 50 ft run of 8 ft × 8 in wall is 1.98 × 5 = 9.9 yd³, before waste.
Poured wall vs block wall
| Feature | Poured wall | Block wall |
|---|---|---|
| What you order | Ready-mix by the cubic yard | Blocks, mortar, and core-fill grout |
| Joints | None, except cold joints | Mortar joint every course |
| Site work | Forms, ties, pump or chute | Masonry crew, scaffold for tall walls |
| Calculator to use | This one | Concrete block calculator |
How to measure your wall
- Length: for a closed foundation, measure along the centerline of the wall. Measuring outside faces counts each corner twice.
- Height: from the top of the footing to the top of the wall, in feet. Stepped footings mean different heights; split the wall into sections.
- Thickness: from your foundation plan. Enter it in inches.
- Openings: subtract large ones; ignore small ones.
Common mistakes
- Swapping height and thickness. Height goes in the Width field in feet. Thickness goes in the Depth field in inches.
- Adding the footing into the wall. Figure walls and footings separately, then add them for one order if they pour the same day.
- Leaving out pilasters and brick ledges. They add concrete. Figure each as its own small box.
- Forgetting reinforcement. Count bars with the rebar calculator.
For the full job, the basement foundation cost calculator gives a per-square-foot budget.
Foundation and retaining walls are structural. Wall thickness, reinforcement, and drainage must follow your approved plans and local code. Have a licensed engineer or contractor confirm the design.
Frequently asked questions
Which field is wall height on this calculator?
The Width field. Read the three inputs as: Length = how long the wall runs, Width = how tall the wall stands, in feet, and Depth = how thick the wall is, in inches. The math is the same box volume either way, so this mapping gives the correct cubic yards.
How much concrete for a basement wall?
A wall 36 ft long, 8 ft tall, and 8 inches thick is 36 × 8 × 0.667 = 192 cubic feet, or 7.11 cubic yards, and 7.82 with 10% extra. For a whole basement, add up all wall lengths along the wall's centerline and run the total once.
What thickness is typical for a poured concrete wall?
8 inches is common for residential foundation walls of ordinary height. Taller basement walls, deep backfill, or poor soil can call for 10 inches or more plus reinforcement. Thickness is set by your foundation plan and local code, not by this calculator.
How does a poured wall differ from a block wall?
A poured wall is cast in one piece inside temporary forms, so it has no mortar joints. A block wall is stacked concrete masonry units with mortar, and often grout and rebar in some cores. Poured walls need forms and a pump or chute; block walls need masons and more time on site.
Should I add waste for a concrete wall pour?
Yes. Tick the 10% box. Forms bulge a little, footings are rarely perfectly level, and some concrete stays in the pump line and hopper. Running short on a wall is worse than on a slab, because the cold joint runs along the wall.
Do I subtract window and door openings?
For small basement windows, usually not; the waste allowance absorbs them. For large openings, subtract each one: width × height × thickness. A 9 × 7 ft garage opening in an 8 in wall removes 9 × 7 × 0.667 = 42 cubic feet, or 1.56 cubic yards.
Estimates only. Verify quantities with your supplier before purchasing.