A banded billing system for data communication service is disclosed. A carrier's billing system maintains in data storage a banded-pricing schedule that divides a continuum of increments of data into a series of contiguous, mutually-exclusive increment-ranges and that specifies for each increment-range a respective cost. At the end of a billing period, the billing system determines a number of increments of data communicated by a given subscriber during the billing period. The billing system then queries the banded-pricing schedule to determine which increment-range the number of increments falls into, and to determine the cost specified by the banded-pricing schedule for that increment-range. The billing system then bills the determined cost to the subscriber, for data communication service in the billing period.