Concrete Wall calculator

Calculate concrete for poured foundation and retaining walls. Cubic yards, bags, ready-mix loads and weight — with a waste margin built in, nothing leaves your browser.

Dimensions

FIG. 01

Quantity

Waste margin

Volume ÷ 27 = cubic yards. Pros order to the nearest ½ yard and add a waste margin — running short mid-pour risks a cold joint.

You need

—cu yd

Order to nearest ½ yd → — · —

Cubic feet

—

Cubic meters

—

80 lb bags

—

60 lb bags

—

Est. weight

—

Best buy

see above

How this is calculated

Wall volume is length × height × thickness. An 8-inch wall is 0.667 ft thick. A 20 ft × 8 ft wall at 8 inches is about 107 cubic feet, or roughly 4 cubic yards — clearly ready-mix territory.

cubic yards = volume in cubic feet ÷ 27 × (1 + waste%)

For the full method and sources, see the methodology page. Comparing buying options? Use the bags-vs-ready-mix calculator.

FAQ

How do I calculate concrete for a wall?

Wall volume is length × height × thickness. An 8-inch wall is 0.667 ft thick. A 20 ft × 8 ft wall at 8 inches is about 107 cubic feet, or roughly 4 cubic yards — clearly ready-mix territory.

How thick should a poured concrete wall be?

Residential foundation walls are commonly 8–10 inches; retaining walls vary widely with height and soil. Wall design is structural — size it with an engineer, not a default value.