1. A method comprising: estimating costs associated with translating a multi-format instruction of a source instruction set architecture (ISA) to a single-format instruction of a target ISA; selecting a format, from a group of formats, the selection based at least in part on the estimated costs for translating the multi-format instruction, wherein the group of formats having a common relationship associated with the multi-format instruction; and translating the selected format to the single-format instruction of the target ISA, wherein estimating the costs comprises accessing and adding together cost estimates, associated with the format, as number of processor cycles.