Prorated billing is a technique for applying standard billing methods to nonstandard billing periods. For example, if a bill for a service is usually invoiced monthly, prorating the bill allows the service provider to bill for an amount that reflects the portion of the month in which the service was used. Prorated billing can be applied to periods shorter or longer than the usual billing period. Some types of prorated billings apply administration charges to compensate the service provider for the accounting expense involved in a billing for a partial billing period.