If an employee works back-to-back consecutive shifts, does he need to be paid overtime for the second shift?

It depends on how the workday is defined. In California, overtime applies to hours worked over 8 in a workday or 40 in a workweek, and double time applies over 12 hours in a workday.

A workday is any fixed 24-hour period (commonly 12:01 a.m. to midnight). Overtime is calculated based on hours worked within that defined workday — not consecutive hours across two workdays.

For example, if an employee works from 4 p.m. to midnight (Day 1) and then 12:01 a.m. to 8 a.m. (Day 2), they worked 16 consecutive hours but did not exceed 8 hours in either