If you run a small business and have employees, then you obviously have to handle payroll. Handling payroll isn't as simple as just paying your employees based on how many hours they have worked and how much their hourly pay rate is. You also have to worry about things like withholdings. You may want to hire a small business payroll service for a number of reasons, including the fact that they can help you with handling withholdings from employee paychecks.
