We have developed a LabVIEW virtual instrument (PAC_Fit.vi) for efficient simulation and analysis of probe approach curve data from a scanning electrochemical microscope (SECM). The virtual instrument (VI) is available for free download and can be used to determine absolute probe height above a substrate, measure rate constants for irreversible electron transfer at a substrate, and perform simulations of SECM approach curves. We anticipate the VI will be of use for educational purposes as well, perhaps as a classroom tool for introducing the principles of SECM. We have applied the VI to an analysis of the dynamic nature of an aluminum alloy (AA2024-T3) substrate immersed in acid solution in which the activity of the substrate increases over time due to dissolution of the passive oxide layer. The value of kapparent is observed to increase by a factor of 40 over an immersion time of approximately 1 h.