In order to accurately calculate billing and working hours, it is helpful to use various tools and methods such as selecting a year and viewing a calendar with working hours for each month, calculating time and multiplying it by an hourly rate, and using an employee cost calculator. Additionally, an average billable time can be used as a reference point and a work hours calculator can determine the number of working hours between specific dates. Excel can also be used to average time and a firm's utilization rate is calculated by dividing the number of billable hours by the total number of hours worked. Finally, converting time to decimals is necessary for calculating payroll or billing and can be easily achieved.