Payroll expense is the amount of salaries and wages paid to employees in exchange for services rendered by them to a business. Payroll expense is the cash paid during an accounting period for salaries and wages. Payroll expense may be a much less substantial proportion of total expenses in a business useful source . Your accountant runs monthly reports, not weekly reports. That is why your accounting department may prefer semi-monthly pay periods, since the last paycheck of the month will typically coincide with the end of the month.