29 C.F.R. § 778.111

(a) Piece rates and supplements generally. When an employee is employed on a piece-rate basis, the regular hourly rate of pay is computed by adding together total earnings for the workweek from piece rates and all other sources (such as production bonuses) and any sums paid for waiting time or other hours worked (except statutory exclusions). This sum is then divided by the number of hours worked in the week for which such compensation was paid, to yield the pieceworker's “regular rate” for that week. For overtime work the pieceworker is entitled to be paid, in addition to the total weekly earnings at this regular rate for all hours worked, a sum equivalent to one-half this regular rate of pay multiplied by the number of hours worked in excess of 40 in the week. (For an alternative method of complying with the overtime requirements of the Act as far as pieceworkers are concerned, see § 778.418.) Only additional half-time pay is required in such cases where the employee has already received straight-time compensation at piece rates or by supplementary payments for all hours worked. Thus, for example, if the employee has worked 50 hours and has earned $491 at piece rates for 46 hours of productive work and in addition has been compensated at $8.00 an hour for 4 hours of waiting time, the total compensation, $523.00, must be divided by the total hours of work, 50, to arrive at the regular hourly rate of pay—$10.46. For the 10 hours of overtime the employee is entitled to additional compensation of $52.30 (10 hours at $5.23). For the week's work the employee is thus entitled to a total of $575.30 (which is equivalent to 40 hours at $10.46 plus 10 overtime hours at $15.69).

(b) Piece rates with minimum hourly guarantee. In some cases an employee is hired on a piece-rate basis coupled with a minimum hourly guaranty. Where the total piece-rate earnings for the workweek fall short of the amount that would be earned for the total hours of work at the guaranteed rate, the employee is paid the difference. In such weeks the employee is in fact paid at an hourly rate and the minimum hourly guaranty is the regular rate in that week. In the example just given, if the employee was guaranteed $11 an hour for productive working time, the employee would be paid $506 (46 hours at $11) for the 46 hours of productive work (instead of the $491 earned at piece rates). In a week in which no waiting time was involved, the employee would be owed an additional $5.50 (half time) for each of the 6 overtime hours worked, to bring the total compensation up to $539 (46 hours at $11 plus 6 hours at $5.50 or 40 hours at $11 plus 6 hours at $16.50). If the employee is paid at a different rate for waiting time, the regular rate is the weighted average of the 2 hourly rates, as discussed in § 778.115.