29 C.F.R. § 778.108

The “regular rate” of pay under the Act cannot be left to a declaration by the parties as to what is to be treated as the regular rate for an employee; it must be drawn from what happens under the employment contract (Bay Ridge Operating Co. v. Aaron, 334 U.S. 446). The Supreme Court has described it as the hourly rate actually paid the employee for the normal, nonovertime workweek for which he is employed—an “actual fact” (Walling v. Youngerman-Reynolds Hardwood Co., 325 U.S. 419). Section 7(e) of the Act requires inclusion in the “regular rate” of “all remuneration for employment paid to, or on behalf of, the employee” except payments specifically excluded by paragraphs (1) through (7) of that subsection. (These seven types of payments, which are set forth in § 778.200 and discussed in §§ 778.201 through 778.224, are hereafter referred to as “statutory exclusions.”) As stated by the Supreme Court in the Youngerman-Reynolds case cited above: “Once the parties have decided upon the amount of wages and the mode of payment the determination of the regular rate becomes a matter of mathematical computation, the result of which is unaffected by any designation of a contrary ‘regular rate’ in the wage contracts.”