The National Institute of Standards and Technology (NIST) released a 31-page report late last month intended to help state regulators craft rules governing the scales used to weigh cannabis products at the point of sale. The document notes that as legal marijuana expands across many states, scale suitability has become increasingly important, and observes that cannabis differs from other regulated commodities such as groceries, precious metals and gems.
NIST identifies five scale characteristics regulators should weigh: accuracy classification, the value of the verification scale interval, monetary value per scale division, auxiliary indication, and minimum capacity paired with recommended minimum load.
On accuracy, the agency notes that treating cannabis like precious metals and requiring Class II precision might seem logical given its high value, but factors such as air buoyancy and moisture content "may not justify" such strict standards. States "should consider this duality when determining the proper accuracy class for scales used in the sale of Cannabis products," the report states.
NIST's handbook currently sets no standard for monetary value per scale division; the report suggests this could become a "User Requirement for all commodities (or all high-value commodities) to avoid being arbitrary towards Cannabis products."
Auxiliary indications, which add extra digits for finer weighing at low weights, are called a "useful feature" but one that risks confusing some buyers.
The report treats the verification scale interval, minimum capacity, and recommended minimum load as linked: minimum-load requirements effectively cap the verification interval, so a marijuana-specific rule separately capping that interval "appears arbitrary," since no equivalent rule exists for other high-value goods under NIST Handbook 44, and would undercut the purpose of the minimum-load requirement.
NIST stresses it isn't pushing specific rules but offering "objective information" for regulators, stating: "These conclusions are intended to clarify the discussion and help regulators and other stakeholders develop a set of requirements for scales used in the sale of Cannabis products, based on scientific analysis."
The findings draw on real-world data collected from cannabis scales in nine states, and the report is available on NIST's website.
This is NIST's latest cannabis-related effort. Last month, the agency added dozens of new marijuana compounds to a government chemical-fingerprint library used to identify unknown substances in food, drugs, cosmetics, the environment, bodily fluids and forensic evidence. In 2025, NIST hosted a workshop on marijuana-breath impairment testing technology, and separately, its researchers reported the first-ever detection of THC in human breath following edible consumption—a potential step toward field testing for cannabis impairment. NIST has also published reports under its Cannabis Laboratory Quality Assurance Program (CannaQAP) and has updated its industry handbook to reflect cannabis-related decisions made by the National Conference of Weights and Measures.
