Concrete Wall Calculator
Calculate cubic yards of concrete for a formed poured wall from its length, height, and thickness, plus total cost.
How this calculator works
A formed, poured concrete wall is a rectangular volume just like a slab, but the dimensions map differently: length is the wall’s length, width is the wall’s height, and depth is the wall’s thickness in inches. This calculator multiplies those three figures and converts to cubic yards.
Formula: Cubic yards = (Length ft × Height ft × Thickness ft) ÷ 27, where Height is entered in the Width field and Thickness is entered in inches in the Depth field.
Worked example
A 20 ft long, 4 ft high wall, 8 inches thick, $150/yd³:
- Thickness in feet: 8 ÷ 12 = 0.667 ft
- Cubic yards: (20 × 4 × 0.667) ÷ 27 ≈ 1.98 yd³
- At $150/yd³, that’s $296.30 before waste.
Coverage reference
| Wall length | Wall height | Thickness | Concrete needed |
|---|---|---|---|
| 10 ft | 4 ft | 8 in | 0.99 yd³ |
| 20 ft | 4 ft | 8 in | 1.98 yd³ |
| 30 ft | 6 ft | 8 in | 4.44 yd³ |
How to measure your wall
Measure the wall’s total length along its base and its height from footing to top in feet, then confirm the thickness called for in your foundation plan (8 inches is a common default). Enter length into the Length field, height into the Width field, and thickness in inches into the Depth field — this mapping is what lets one calculator handle both slabs and walls correctly.
Frequently asked questions
Which field is wall height on this calculator?
The Width field. This calculator's fields are labeled length, width, and depth, but for a poured wall you should read them as: Length field = wall length, Width field = wall height, Depth field = wall thickness in inches. Entering height into the width field is intentional and gives the correct volume.
What thickness is typical for a poured concrete wall?
8 inches is the common default for residential foundation walls, though basement walls carrying significant backfill or taller retaining walls may call for 10-12 inches. Thickness is a structural decision that should match your foundation plan or an engineer's spec.
How does a formed poured wall differ from a block wall?
A poured wall is cast as one continuous piece inside temporary forms, giving it more uniform strength and fewer water-entry points than a stacked concrete block wall, which relies on mortar joints. Poured walls generally cost more upfront but need less waterproofing maintenance over time.
Should I add waste for a concrete wall pour?
Yes, 5-10% is standard to account for form seepage, minor overfill, and the concrete left in the truck's chute and pump lines. Wall pours in particular tend to lose a bit more to the pumping process than flatwork does.
Do I need to account for window and door openings in a wall?
For a rough estimate, small openings usually aren't worth subtracting since the buffer from waste covers the difference. For walls with large openings — garage doors, wide window banks — subtract that area's volume separately for a tighter number.
Estimates only. Verify quantities with your supplier before purchasing.