Concrete Wall Calculator — ft to cu yd, bags, cost
How to use this calculator
Pick a wall layout, type length/height/thickness in feet + inches (⅛″ fractions), and deduct openings. The output sizes the ready-mix truck or bag count, the plywood and tie quantity for the formwork, and the rebar grid before you call the supplier.
Cost — pick ready-mix truck per yd³, 80 lb bags, or 60 lb bags for material cost.
Reinforcement — horizontal and vertical rebar #3–#6 with spacing 6″–24″ o.c. per ACI 318-19, including lap splices.
Labor — rate per ft² of formwork (contact area), per yd³, or flat price. Grand total sums all active sections.
Saved Calculations
| Time | Config | Length | Vol yd³ | Concrete $ | Rebar | Rebar $ | Labor | Total |
|---|
How to Calculate Concrete for a Poured Wall
Pick the wall layout that matches your pour — a single wall, an L-shape (two walls at a corner), a U-shape (back plus two returns), or a closed rectangle. Enter length, height, and thickness in feet, inches, and fractions, then deduct door and window openings so the volume reflects the actual concrete placed. Wall thickness drives both volume and structural capacity: 8″ is typical for foundation walls up to 7 ft of unbalanced backfill, 10–12″ for taller basement and retaining walls. If you only need plain volume without formwork and rebar, the simpler concrete volume calculator covers slabs, footings, and rectangular pours.
Wall Volume Formula
Volume = Total Wall Length × Height × Thickness − (Openings × Avg Width × Avg Height × Thickness). Cubic feet ÷ 27 = cubic yards. Concrete at 150 lb/ft³ weighs about 4,050 lb/yd³. Formwork (contact) area is both faces of the wall, 2 × Length × Height — that figure sizes plywood, ties, and the bulk of the labor. Order 5–10% extra for spillage, over-excavation, and form deflection. For bagged pours, compare bag counts here against the dedicated concrete bag calculator.
Reinforcement per ACI 318-19
Walls carry both horizontal and vertical steel. ACI 318-19 §11.6 sets minimum ratios of 0.0012 (horizontal) and 0.0015 (vertical) of gross concrete area for deformed bars up to #5; #4 at 12″ o.c. each way is the common residential grid. This tool counts rows and bars, adds lap splices at 40 d_b, applies cutting waste, and converts to standard 20 ft sticks. For isolated members use the concrete beam calculator or the concrete column calculator, which size longitudinal bars and stirrups directly.
On pour day
Three things wall estimators forget. Short-load fee — most plants charge $80–150 when you order under ~3 yd³, so a 20 ft × 8 ft × 8″ single wall (≈4 yd³) is the breakpoint where ready-mix beats bags. Formwork is the budget — the concrete itself is $160–200/yd³ delivered in most US markets in 2025, but forming, pouring, and stripping adds $8–15/ft² of contact area; on an 8 ft basement wall that's roughly $130–240 per linear foot before rebar. Mix grade and admixtures — basement and retaining walls in freeze-thaw regions need 4000 psi with air entrainment per ACI 318-19 §19.3, which adds ~$10/yd³ vs. a 3000 psi residential mix; bring up the mix design before the truck arrives, not after. Pump trucks ($700–1,200/day) are usually required for basement walls when a chute can't reach the form, and you should also check IRC Table R404.1.2(1) for minimum wall thickness vs. backfill height. Curbs and steps along the wall can be priced with the curb & gutter calculator and the concrete stairs calculator.
FAQ
How thick should a concrete wall be? Foundation walls: 8″ minimum for up to 7 ft of unbalanced fill; 10″ for up to 8 ft; 12″ for retaining walls over 8 ft of retained earth, per ACI 318-19 and IRC Table R404.1.2(1).
How much concrete do I need for a basement wall? A 30 ft × 20 ft basement with 8 ft high, 8″ thick walls is ~100 ft of perimeter × 8 ft × 0.67 ft ≈ 533 ft³ ≈ 19.7 yd³ before waste — about 20.7 yd³ at 5% waste.
Does the calculator subtract openings? Yes. Enter the count and average opening size; the deducted volume is count × width × height × wall thickness, which also reduces the net formwork shown.
