This paper proves that critical geometric dimensions of a capacitive resonator can be estimated from nondestructive electrical measurements. In particular, the gap between the electrodes at rest is precisely determined. The imperfect verticality of flanks introduced by defects of the manufacturing process is also quantified. The presented approach is especially interesting compared to time-consuming observations with conventional microscopy techniques (optical, SEM,…) which are complex to automate. Furthermore, it is the first available nondestructive way to determine the fabrication defects coming from imperfect etching processes such as DRIE. After presenting the theoretical developments, experimental characterization is performed on a fabricated capacitive comb drive resonator. The estimated parameters are compared to optical microscope observations. Our method paves the way to novel reverse-engineering techniques, simultaneously combining process control and system characterization.