Also, would plant tilities and depreciation be considered overhead?
The predetermined overhead rate is estimated annual overhead costs divided by the estimated total activity base amount. The activity base can be anything they want, but commonly used ones are direct labor hours, direct labor dollars, and machine hours. And yes those are overhead costs. ALL costs that are related to production in any way, or related to the factory building in any way, but are not direct materials or direct labor, are overhead costs. So indirect materials, indirect labor, depreciation, factory supplies, insurance & taxes on the building, etc. are all overhead.
