Why a cubic yard is 27 cubic feet, not 3 — the volume formula in feet and inches
A yard is 3 ft, but a cubic yard cubes it: 3 × 3 × 3 = 27 ft³ — not 3. Volume = L × W × depth ÷ 27 (depth in feet), or ft² × depth(in) ÷ 324 (324 = 12 × 27). A 10 × 12 ft slab 4 in thick is 1.48 yd³.
What this diagram shows
A diagram correcting the most common bulk-material mistake. An isometric cube measures 3 feet on every edge and is divided into a 3-by-3-by-3 grid of 27 unit cubes, labeled 27 cubic feet, which is one cubic yard — a red tag warns it is not 3 cubic feet, because a yard is 3 feet but a cubic yard cubes it, 3 times 3 times 3. A formula card gives the two forms the calculator uses: with depth in feet, cubic yards equal length times width times depth divided by 27; with depth in inches, cubic yards equal the square-foot area times the inch depth divided by 324, where 324 is 12 inches per foot times 27 cubic feet per cubic yard. A worked example takes a 10 by 12 foot slab 4 inches thick: 120 square feet times 4 divided by 324 equals 1.48 cubic yards, and the check, 120 times one-third of a foot equals 40 cubic feet divided by 27, gives the same 1.48.
Cubic Yards Calculator
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