August 2002 

Intent and Scope of NIST Handbook 133 

By: Tom Coleman 

NIST Handbook 133 was prepared for use as a procedural guide for compliance testing of 

net content statements on packaged goods. Compliance testing of packaged goods is the 

determination of the conformance of the results of the packaging, distribution, and 

retailing process (the packages) with specific legal requirements for net content 

declarations. The handbook was primarily developed for use by government officials, 

although it should be useful to commercial and industrial establishments in the areas of 

packaging, distribution, and sale of commodities. Routine verification of the net contents 

of packages is an important part of any weights and measures program to facilitate value 

comparison and fair competition. The procedures in this handbook are recommended for 

use to verify the net quantity of contents of packages kept, offered, or exposed for sale, at 

any location (e.g., at the point of pack, in storage warehouses, -retail stores, and 

wholesale outlets). Any commodity sold by weight, measure, or count may be tested. 

Regardless of where the test occurs (point of pack, wholesale, or retail), each test or 

“inspection lot” must meet the following criteria: 

The net quantity of content statement must be “accurate,” but reasonable variations are 

permitted. In general, the average net quantity of contents of packages in a lot must at 

least equal the net quantity of contents declared on the label. Plus or minus variations 

from the declared net weight, measure or count are permitted when caused by 

unavoidable variations in weighing, measuring, or counting the contents of individual 

packages that occur in current good manufacturing practice. Such variations must not be 

permitted to the extent that the average of the quantities in the packages of a particular 

commodity or lot (large or small) of the commodity is kept, offered, or exposed for sale 

or sold is below the stated quantity. 

The variation of individual package contents from labeled quantity must not be 

“unreasonably large.” Under-filled packages by more than the Maximum Allowable 

Variation specified for the package are considered unreasonable errors. Unreasonable 

shortages are not generally permitted, although overages in other packages in the same 

lot, shipment, or delivery compensate for such shortage. The handbook does not specify 

limits of overfilling. 

Generally, the inspection lot is the collection of identically labeled packages available for 

inspection at any location (retail, wholesale, point of pack) in the distribution chain. This 

collection of packages will pass or fail as a whole based on the results of tests on a 

sample drawn from this collection. If the inspection lot fails, no further testing is 

required although, “follow up” inspections are encouraged. After the evaluation of an 

inspection lot is reached, the jurisdiction should consider if any further investigation is 

warranted. An effective net content testing program typically includes testing at all levels 

of distribution; however, the Committee recognizes this is not always possible. Although 
“follow up” inspections are not required to support the determination when a lot has 

failed a compliance test, the Committee encourages weights and measures officials to 

work with other jurisdictions to solve problems and obtain corrective actions.