Payroll is the sum total of all compensation a business must pay to its employees for a set period of time or on a given date. It is usually managed by the accounting department of a business; small-business payrolls may be handled directly by the owner or an associate. Payroll can also refer to the list of employees of a business and the amount of compensation due to each of them. It is a major expense for most businesses and is almost always deductible as such. Payroll can differ from one pay period to another due to overtime, sick pay and other variables.