A weighmaster is an individual or company who weighs, measures, or counts a product and issues a statement or memorandum of the weight, measure or count which is used as the basis for either the purchase or sale of that product or charge for service. Weighmasters or their deputy weighmasters perform the weighing, measuring, or counting and issue the weighmaster certificate for the company.

In concert with state officials, county inspectors monitor licensed weighmasters by auditing records kept by local businesses. Program activities include reweighing of vehicles and containers to verify the net weight statements on weighmaster certificates, spot inspections of establishments involved in bulk sales through the use of undercover sales or purchases of commodities, and investigations of complaints alleging fraudulent use or misuse of weighmaster certificates.