Concrete Wall Calculator
Length × height × thickness, minus openings, plus the right waste factor. The notes below cover the part calculators can't do: getting the concrete into the form safely.
- 1 yd³
- per 40 ft² of 8 in wall
- 4–5 ft/hr
- safe pour rate @ 70°F
- 5–6 in
- target slump for walls
- 2 sides
- of formwork required
Concrete Wall Calculator
Cast-in-place walls: foundations, retaining walls, stem walls. Subtracts window and door openings.
Wall volume math, with openings
V = (L × H − A₀) × t × (1 + waste)
- L
- wall length (ft or m)
- H
- wall height (ft or m)
- A₀
- total area of openings (ft² or m²)
- t
- wall thickness (ft or m)
Corners are counted once: measure lengths along the wall centerline, or measure outside faces and accept ~1% overage on a rectangular foundation.
For a full foundation, run each wall face through the calculator (or sum the centerline perimeter and treat it as one long wall). Remember the footing below is a separate volume — the footing calculator handles that, and the two pours are usually days apart anyway.
Worked example: basement with a walkout
A 36 × 28 ft basement, 8 ft walls, 8 in thick. One walkout door (7 × 4 ft) and four window bucks (each 32 × 16 in).
- 1
Centerline perimeter
2 × (36 + 28) = 128 ft
- 2
Gross wall face
128 × 8 = 1,024 ft²
- 3
Openings
28 ft² (door) + 4 × 3.6 ft² = 42.2 ft²
- 4
Net face × thickness
(1,024 − 42.2) × 0.667 = 654.8 ft³
- 5
Add 10%, convert to yards
654.8 × 1.10 ÷ 27 = 26.7 yd³
Result: Order 27 yd³ — that's three 9-yard trucks, so sequence them 45 minutes apart.
Formwork pressure: the safety constraint
Concrete per square foot of wall
Yards per 100 ft² of wall face — memorize your thickness and you can estimate standing in the excavation.
Wall pour questions
- How much concrete is in an 8-inch foundation wall?
- An 8 in wall holds 0.667 ft³ per square foot of wall face — almost exactly 1 yd³ per 40 ft² of wall. A typical 8 ft tall, 40 ft long wall face (320 ft²) therefore needs about 8 yd³ before waste.
- Should I subtract window and door openings?
- Yes, when they're large. A single basement window buck (say 32 × 16 in ≈ 3.5 ft²) is noise inside the waste allowance, but a walkout door plus three windows in one wall can exceed 60 ft² — nearly 1.5 yd³ in an 8 in wall. The calculator's openings field handles this.
- How fast can I fill a wall form?
- Form pressure is governed by pour rate and concrete temperature (ACI 347). Standard residential panel forms are commonly rated around 600–800 psf, which at 70°F works out to roughly 4–5 ft of placement per hour. Filling a full-height 8 ft wall in one fast pass can blow out forms — pour in lifts around the wall instead.
- What slump should wall concrete be?
- 5–6 in slump places well in walls; anything stiffer honeycombs around rebar and anything wetter is usually water added on site, which cuts strength (each added gallon per yard costs roughly 200 psi). Order a mid-range water-reducer mix rather than adding water at the truck.
- Is an ICF wall calculated the same way?
- The concrete core is — length × height × core thickness (typically 6 or 8 in) minus openings. The foam form adds no concrete. ICF suppliers publish per-form volumes; they agree with this calculator to within a percent or two.
Compare your wall estimate against ready-mix pricing in the cost guide
Related calculators & guides
Sources & references
- [1]ACI 347R-14: Guide to Formwork for Concrete — American Concrete Institute, 2014
- [2]ASTM C94/C94M: Standard Specification for Ready-Mixed Concrete — ASTM International, 2024
- [3]ACI 318-19: Building Code Requirements for Structural Concrete — American Concrete Institute, 2019