Use a cone only when a pile is close to a circular base and tapers to one peak. Measure its ground-level diameter and vertical height; add a product-specific bulk density if weight matters.

Formula: cubic yards = π × (diameter ÷ 2)² × vertical height ÷ 3 ÷ 27

Worked example

An ideal cone 18 ft across and 6 ft high contains about 509 ft³, or 18.85 yd³. At an illustrative 2,800 lb/yd³ bulk density, that would weigh about 26.39 US short tons.

Geometry comes before density

The cone equation uses one-third of base area times height. OpenStax gives the right-circular-cone formula. Divide cubic feet by 27 to get cubic yards. Diameter must be the full width of the base, not its radius.

A real pile can depart from a cone

A flattened top, irregular footprint, sidewall or multiple peaks make this idealized shape inaccurate. Measure the actual footprint and profile for inventory or contract work. The calculator does not add a hidden compaction or swell factor.

Weight needs the matching bulk density

If entered, density is multiplied by the estimated yardage and divided by 2,000 pounds per US short ton. Use a supplier or measured density for that same material state. An empty density field leaves weight uncalculated rather than guessing from a material name.

Explore the related calculation

For a different starting point, try the bulk-density guide or return to the main calculator. Browse the complete tool directory for this site.

Reference and corrections

The definitions and assumptions above follow these sources; the examples and calculator arithmetic are original to this page.

Found a problem? Email contact@cubicyardstotons.org.

Conical stockpile volume calculator

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