By definition, overhead cannot be traced directly to jobs.  Most company use a predetermined overhead rate (or estimated rate) instead of actual overhead for the following reasons:

•Some overhead costs, like factory building depreciation, are fixed costs. If the volume of goods produced varies from month to month, the actual rate varies from month to month, even though the total cost is constant from month to month. The predetermined rate, on the other hand, is constant from month to month.

•Predetermined rates make it possible for companies to estimate job costs sooner. Using a predetermined rate, companies can assign overhead costs to production when they assign direct materials and direct labor costs. Without a predetermined rate, companies do not know the costs of production until the end of the month or even later when bills arrive. For example, the electric bill for July will probably not arrive until August. If Creative Printers had used actual overhead, the company would not have determined the costs of its July work until August. It is better to have a good estimate of costs when doing the work instead of waiting a long time for only a slightly more accurate number.

Predetermined overhead rates

Predetermined overhead rates are used to apply overhead to jobs until we have all the actual costs available.  To create the rate,  we use cost drivers to assign overhead to jobs. A cost driver is a measure of activities, such as machine-hours, that is the cause of costs. To assign overhead to jobs, the cost driver should be the cause of the overhead costs, or at least be reasonably associated with the overhead costs. Just as automobile mileage is a good cost driver for measuring the cause of gasoline consumption, machine-hours is a measure of what causes energy costs. By assigning energy costs to jobs based on the number of machine-minutes or hours the job uses, we have a pretty good idea of the energy costs required to produce the job.