Ans - The main difference between a semi-monthly and bi-weekly pay period lies in the frequency of payment. A semi-monthly pay period involves receiving a paycheck twice a month, typically on the 15th and the last day of the month. In contrast, a bi-weekly pay period means an employee is paid every two weeks, resulting in 26 paychecks per year, compared to 24 paychecks in a semi-monthly pay period. The key distinction is that a semi-monthly pay period is based on the calendar, while a bi-weekly pay period is based on a two-week cycle, regardless of the number of days in the month. Understanding the difference between semi-monthly vs bi-weekly pay periods is essential for employees to manage their finances effectively.