North Carolina General Statutes Chapter 105. Taxation § 105-164.10. Retail tax calculation

For the convenience of the retailer in collecting the tax due under this Article, the Secretary must prescribe tables that compute the tax due on sales. The Secretary must issue a separate table for each rate of tax that may apply to a sale. A retailer is not required to collect tax due under this Article based on a bracket system.

In computing tax due under this Article, the tax computation must be carried to the third decimal place and must round up to the next cent whenever the third decimal place is greater than four. A person liable for tax under this Article may elect to compute the tax due on a transaction on an item or invoice basis and the rounding rule is applied to the aggregate tax due.