Concrete Wall Calculator: Yards for Poured Walls
A poured concrete wall 20 ft long, 4 ft high and 8 in thick needs 1.98 cubic yards, or 2.17 yd³ with 10% extra.
Advanced options: waste, prices
NRMCA advises ordering 4 to 10 percent over the estimate.
Concrete needed (with 10% extra)
2.17 yd³
1.66 m³ · 53.33 ft³ before extra
Wall: 20 ft × 4 ft × 8 in × 0 sq ft. Over about 1 yd³: order ready-mix.
Premix bags
- 80 lb98
- 60 lb131
- 50 lb157
- 40 lb196
- Ready-mix cost
- $348
- Weight
- 8,000 lb
Full breakdown
| Volume before extra | 1.98 yd³ · 1.51 m³ |
|---|---|
| With 10% extra | 2.17 yd³ |
| Weight (150 lb/ft³) | 8,000 lb · 4 tons |
| Pallets of 40 lb (80 bags each) | 3 |
| Pallets of 60 lb (56 bags each) | 3 |
| Pallets of 80 lb (42 bags each) | 3 |
| Truckloads at 12 yd³ | 1 |
| Truckloads at 8 yd³ | 1 |
Bag counts round up, as Quikrete's own calculator does. Cost uses your prices; delivery and short-load fees are extra.
Key takeaways
- A 20×4 ft wall 8 in thick needs 2.17 yd³ with 10% extra.
- Subtract door and window openings before ordering.
- Poured walls almost always need ready-mix (over 1 yd³).
- Retaining walls over 48 in of fill need an engineer (IRC R404.4).
How Much Concrete Do I Need for a Wall?
You need the wall's length × height × thickness, minus openings, divided by 27, plus 10% extra. A wall 20 ft long, 4 ft high and 8 in thick holds 53.33 ft³, or 1.98 yd³ (1.51 m³). With 10% extra, that is 2.17 yd³.
Concrete Wall Formula
yd³ = [Length (ft) × Height (ft) − Openings (sq ft)] × (Thickness (in) ÷ 12) ÷ 27Subtract door and window openings as square feet; the calculator has an openings field for this.
How Many Yards of Concrete for a Wall?
Wall concrete in cubic yards, with 10% extra, is listed by size and thickness.
| Wall (length × height) | 6 in | 8 in | 10 in |
|---|---|---|---|
| 20×4 ft | 1.63 | 2.17 | 2.72 |
| 40×4 ft | 3.26 | 4.35 | 5.43 |
| 40×8 ft | 6.52 | 8.69 | 10.86 |
| 100×8 ft | 16.30 | 21.73 | 27.16 |
How Thick Is a Poured Concrete Wall?
Poured concrete basement walls are commonly 6, 8 or 10 in thick; the 2021 IRC gives reinforcement tables for 6 in, 8 in and 10 in nominal flat walls (Section R404.1.2). The required thickness depends on wall height, soil and backfill, so follow the local code tables.
Retaining Wall Concrete: Stem and Footing
A poured retaining wall uses concrete for the stem and the footing under it. The default retaining wall in the calculator (20 ft long, 4 ft stem, 8 in thick, 2×1 ft footing) needs 3.46 yd³ before extra. Retaining walls above local height limits need an engineer's design.
Bags or Ready-Mix for a Wall?
Ready-mix suits most poured walls, because a wall passes 1 yd³ quickly, the switch point that is this calculator's own rule. Ready-mix also keeps a wall pour continuous, with no cold joints between batches.
How Much Does a Poured Concrete Wall Cost?
Concrete for a 20×4 ft wall at 8 in costs about $348–$424 at $160 to $195 per yd³ (Concrete Network). Forms, rebar and labor are extra.
Worked Examples: Three Walls
Garden wall, 30×3 ft, 6 in thick. 30 × 3 × 0.5 = 45 ft³ = 1.67 yd³; with 10% extra, 1.83 yd³.
Basement wall, 40×8 ft, 8 in thick, with a 3×7 ft door. (320 − 21) × 0.667 = 199.3 ft³; with 10% extra, 8.12 yd³.
Foundation wall, 100×4 ft, 10 in thick. 333.3 ft³ = 12.35 yd³; with 10% extra, 13.58 yd³, or 2 trucks at 12 yd³.
How Much Does a Concrete Wall Weigh?
A poured wall weighs about 150 lb per cubic foot (this calculator's design density), so a 20×4 ft wall 8 in thick weighs about 8,000 lb, or 400 lb per linear foot.
Poured Wall vs Block Wall
A poured wall needs forms and usually a truck; a block wall needs blocks, mortar and core fill. Count blocks with the block calculator, and size the footing under either wall with the concrete footing calculator.
Wall Concrete by Square Feet
Wall concrete per square foot of wall face depends only on thickness: 6 in = 0.5 ft³, 8 in = 0.667 ft³, 10 in = 0.833 ft³.
| Wall face area | 6 in (yd³ + 10%) | 8 in (yd³ + 10%) | 10 in (yd³ + 10%) |
|---|---|---|---|
| 80 sq ft | 1.63 | 2.17 | 2.72 |
| 160 sq ft | 3.26 | 4.35 | 5.43 |
| 320 sq ft | 6.52 | 8.69 | 10.86 |
| 800 sq ft | 16.30 | 21.73 | 27.16 |
Concrete Wall Calculator FAQ
How many yards of concrete for a 100 ft wall?
A 100 ft wall 4 ft high and 8 in thick needs 10.86 yd³ of concrete with 10% extra.
Next step
Size the footing with the concrete footing calculator, and for walls holding back soil use the retaining wall concrete calculator.
Official sources
Last reviewed 2026-11-05. Numbers come from our tested engine; see how we calculate and our sources.