SoftExplorer is a tool that can estimate the power and energy consumption of an algorithm directly from the C program, or from the assembly code. Estimation is based on a power model of the targeted processor, obtained through a Functional Level Power Analysis. Five power models have been developed so far, for the Texas Instrument's DSP C67, C64, C62 and C55, and for the RISC ARM7. SoftExplorer proves to be a precious help in the development of DSP applications. We show how to quickly find ”hot” parts of an algorithm, to determine the best data mapping, or to choose the less consuming processor / frequency couple.