System and method for calibrating a step attenuator. N attenuation measurements of a step attenuator may be received, where the step attenuator includes M series-connected attenuation sections. Each attenuation section may be configured to switchably provide a respective level of attenuation, where N is greater than M, and where the step attenuator may be modeled via M+1 coefficients, including a coefficient for a no-attenuation state and respective coefficients for the attenuation sections. Values of the coefficients may be determined via least squares estimation using the N attenuation measurements, thereby calibrating the step attenuator.