A punch clock is a timekeeping device which is used to record data about when employees arrive at and leave work. The data from a punch clock is utilized during payroll to determine how much each employee should be paid. This data may also be inspected by officials who enforce labor laws, looking for signs that employees are staying beyond legal working hours.
There are two components to a punch clock: the clock itself, and the “time card” on which data is recorded in a process known as punching or punching in. Traditionally, data was recorded on punch cards, paper or plastic cards which were physically stamped or punched by the clock, and punch cards are still used in some workplaces today. Modern time cards also come in a variety of guises, including cards with magnetic strips which are swiped through a punch clock, and wireless fobs which are waved at the punch clock. In all cases, the goal of the time card design is to ensure that data about the employee's work habits is recorded consistently and accurately.
The earliest punch clocks were developed in the mid-1800s in response to a desire to be able to record employee data accurately and efficiently. Without a punch clock, employers had to rely on an official stationed by the door to check employees in and out, or on the word of the employees. Punch clocks streamlined the process, and reduced the possibility of fraud. Most modern workplaces which pay hourly wages use a punch clock model to track their employees.
From the point of view of employers, the biggest potential problem with a punch clock is that it can be gamed. For example, an employee could punch his or her card and the card of a friend in the morning, and someone leaving late could punch a stack of cards belonging to friends to make it look like everyone stayed late. In some egregious cases, employees have been known to create false identities and punching their time cards for the purpose of getting two paychecks. Some punch clocks have gotten around this problem by requiring biometric information such as thumb prints, or by obliging employees to enter passcodes before their times are recorded, under the assumption that employees may not trust each other with their passcodes.
While some employees dislike having to punch in, the punch clock has some distinct advantages for employees. For one thing, the punch clock is a neutral arbiter, recording all information about an employee's hours. If an employee suspects that he or she is being cheated, an audit of the relevant time card can be requested. A punch card with security measures can also be used to prove that an employee was present at the workplace, in the event that an alibi is needed. Furthermore, the data on time cards can be used to refute claims that an employee is chronically late or prone to leaving early.