Eighth (3.5g)

An eighth is one-eighth of an avoirdupois ounce — the most common mid-size flower purchase unit in U.S. cannabis retail. Exact conversion: 28.349523125 g ÷ 8 = 3.5437 g, universally rounded to 3.5 g on dispensary menus and state seed-to-sale tracking systems. The unit is an artifact of U.S. illicit-market imperial conventions that persisted after legalization; Colorado, Washington, California, and other state regulators permit "3.5 g" labeling as equivalent to ⅛ oz for possession-limit purposes. Caulkins and colleagues document the entrenchment of ⅛/¼/½/oz units in U.S. illicit pricing data. Note — retail vs. exact: Dispensary "eighths" sold as 3.5 g are ~1.2% lighter than a true avoirdupois ⅛ oz. Citations: Caulkins JP, Kilmer B. Addiction. 2016;111:2082-2089; Colorado Marijuana Enforcement Division, 1 CCR 212-3; NIST SP 811.