Idaho Code § 71-229: United States and metric systems jointly recognized.

The system of weights and measures in customary use in the United States and the metric system of weights and measures are jointly recognized, and either one (1) or both of these systems shall be used for all commercial purposes in the state of Idaho. The definitions of basic units of weight and measure, the tables of weight and measure, and weights and measures equivalents as published by the national bureau of standards or its successor organization, the national institute of standards and technology, are recognized and shall govern weighing and measuring equipment and transactions in the state.