The company estimates that it will have $1,250,000 in overhead costs in 2015. The company believes that employees will work 200,000 hours and that 150,000 machine hours will be used during 2015. Calculate the predetermined overhead rate assuming that the company uses direct labor hours to allocate overhead to jobs. Predetermined overhead rate is estimated overhead divided by estimated activity. From these, the overhead rate equation is a matter of simple division. Overhead rate = Overhead cost / productivity (labor hours, labor cost, machine hours, etc.) Overhead Rate Calculation. Once the proper data is available overhead rate calculations are quite simple. If: Overhead Cost = $5,000 Labor Cost = 100. Rate of Overhead = $5,000 / 100 = 50