Abstract: A client of a metering service defines mapping data and derivation instructions comprising schema metadata and predicate metadata. The metering service provides usage information for a set of computing resources provided by one or more services of a computing resource service provider. As computing resources are utilized, usage records are generated. A derivation system may obtain one or more usage records and determine whether a predicate applies. If the predicate applies, a derivation function may be executed. For example, the derivation function may generate, from an original usage record, a derived usage record using mapping data provided by a client.