Disclosed herein are representative embodiments of methods and apparatus for managing and allocating hardware resources during RTL synthesis. For example, in one exemplary method disclosed herein, an RTL description of a circuit to be implemented in a target architecture is received. The target architecture of this embodiment comprises a fixed number of hardware resources in a class of hardware resources. One or more operator instances are determined from the RTL description received, where at least some of the operator instances are implementable by the hardware resources in the class of hardware resources. In this embodiment, and prior to initially synthesizing the RTL description into a gate-level netlist, assignment information indicative of how the operator instances are to be implemented using the hardware resources in the class of hardware resources is automatically determined. A graphical user interface is also provided that allows a user to view and modify the assignment information.