NIST provides the authoritative U.S. customary to SI conversion factors underlying these values, including the exact relationship 1 ft³ = 0.028316846592 m³, derived from the international foot definition of 0.3048 m.

Common concrete-volume units in U.S. construction reference include cubic inches (in³), cubic feet (ft³), cubic yards (yd³), liters (L), and cubic meters (m³).

Why Concrete Uses Cubic Units

Concrete fills three-dimensional space, so quantity is calculated as V = L × W × H, with length, width, and height (or thickness) all contributing to the final volume. That is why volume is always expressed in cubic units rather than linear or square units.

Particularly useful when reconciling U.S. ready-mix orders in cubic yards with international construction documents specified in cubic meters.

This conversion deserves equal prominence to yd³ → m³, since many users encounter metric quantities in imported plans or international documentation and need to translate that into U.S. ready-mix yardage.

Particularly useful for packaged concrete products, since U.S. manufacturer data sheets typically list yield in cubic feet while metric packaging lists the equivalent in liters.

This conversion is useful but secondary compared with the more common ft³ ↔ yd³ relationship covered above.

Why Gallons Are Secondary for Concrete Quantity

Gallons are more commonly useful for water, admixture dosing, and container-volume context, while concrete quantity itself is normally expressed in cubic feet, cubic yards, or cubic meters in the United States.

In the United States, small quantities are typically expressed in ft³ and ready-mix orders in yd³. On metric projects, concrete quantities use m³ and small packaged quantities use liters. NIST cautions that SI and inch-pound values in technical standards may be treated as independent systems rather than assumed to be exact specification equivalents; ASTM C138/C138M makes the same point for its SI and inch-pound versions.

NIST’s simplified conversion tables intentionally use rounded factors for everyday reference, while its detailed SI conversion-factor tables provide greater precision for technical work.

Multiply When Converting to a Smaller Unit

Example, yd³ → ft³: 2 yd³ × 27 = 54 ft³.

Divide When Converting to a Larger Unit

Example, ft³ → yd³: 54 ÷ 27 = 2 yd³.

Use a Defined Conversion Factor for Metric Conversions

Examples: ft³ × 0.028316846592 = m³, and yd³ × 0.7645549 = m³.

Thickness Given in Inches

Convert first: T(ft) = T(in) ÷ 12.

For full project-volume calculation across shapes and applications, use the concrete volume calculator or the concrete calculator.

See the concrete calculator, concrete slab calculator, and Concrete Slab Thickness Chart for full project-specific slab planning.

A standard 80-lb bag of bagged concrete mix has a published yield of approximately 0.60 ft³. Converting that to cubic yards: 0.60 ÷ 27 ≈ 0.02222 yd³. This demonstrates that bag yield is simply another volume that can be converted using the same formulas above. For complete bag-size yield data, see the Concrete Bag Yield Chart.

Full coverage tables across many thicknesses live on the Concrete Coverage Chart, not here. This section exists only to show the bridge between a converted volume and the area it can cover.

ASTM C138/C138M covers determination of fresh-concrete density and provides formulas for yield and relative yield, defining yield as the volume of concrete produced from known quantities of component materials. That is a fundamentally different concept from simply converting a known volume between units.