There are several types of pay periods, but the four most common are:

1. Weekly: In a weekly pay period, employees are paid every week, typically on the same day each week. This results in 52 paychecks per year for employees paid weekly.
2. Biweekly (or Fortnightly): In a biweekly pay period, employees are paid every two weeks, usually on the same day of the week, resulting in 26 paychecks per year. Biweekly pay periods are common in many organizations.
3. Semimonthly (or Bi-Monthly): In a semimonthly pay period, employees are paid twice a month, typically on specific days such as the 15th and the last day of the month. This results in 24 paychecks per year.
4. Monthly: In a monthly pay period, employees are paid once a month, typically on the same day each month. This results in 12 paychecks per year.

The choice of pay period frequency can vary by employer and industry. Each pay period type has its advantages and challenges, and the choice often depends on factors such as company policy, employee preferences, budgeting needs, and administrative considerations.