Tennessee Code Title 47. Commercial Instruments and Transactions § 47-50-122

(a) If a private entity, or its employees or contractors, is engaged in business with the public and accepts cash payments, or a financial institution provides currency in exchange for a payment instrument received, but does not have exact change available during a cash transaction, then the entity may, in lieu of calculating the total transaction amount to the nearest penny, round off all figures used in the total transaction amount to the nearest nickel, subject to the following conditions:

(b) For purposes of subsection (a), the hundredths place is used to determine the cents in which a total amount ends.

(c) Rounding to the nearest nickel does not apply to transactions conducted electronically.  For mixed-tender transactions, rounding to the nearest nickel applies only to the portion of the transaction paid in cash.  Rounding under this section does not alter or affect the exact amounts authorized, cleared, or settled through any non-cash payment system.

(d) This section does not affect the rounding rule in § 67-6-504(h) for computing the sales tax due in a transaction, and does not relieve private entities from the duty to calculate sales tax to the penny and remit to the department of revenue the exact amount of sales tax shown on an invoice or receipt.