We present a new resource static analysis for the pi-calculus that provides upper bounds on the number of reactions that might occur at runtime for a given process. This work is complementary to previous results on termination of processes by capturing strictly more processes, since it captures all the strongly normalizing processes, and by providing precise upper bounds on the number of communications on each channel. For that purpose, it combines interpretation methods, inspired by polynomial interpretations introduced in order to study the complexity of term rewrite systems, with a notion of resource process that mimics reaction keeping information about resource consumption in terms of communication. We also show that presented analysis is general and can be easily adapted to study space properties of processes (for example, upper bounds on the size of the maximal value sent on a given channel during reaction).