Abstract: A lightweight portable utility billing apparatus is described for enabling a utility (private or public) meter reader to: (1) read utility meters of a number of utility customers on a selected route and obtain current meter value information from each customer; (2) record the current meter value information; (3) automatically calculate the customer utility charges; (4) print customer bills containing the calculated charges thereon; and (5) deliver the customer bills to the customer. The apparatus includes a single input/output magnetic tape for mass data storage and an electronic alterable read only memory (EAROM) for storing the utility rate tables. The EAROMS may be readily updated by the magnetic tape. A keyboard, display and impact printer are included as I/O devices with respect to a microprocessor controller that is programmed by an instructional control program stored in a nonvolatile read only memory.