An electronic device includes a controller, a non-transitory computer-readable storage medium including memory cells having a plurality of threshold voltage distributions and storing operation codes executable by the controller. Based on the operation codes, controller is configured to: calculate average threshold voltages of the plurality of threshold voltage distributions and set a temporary read voltage corresponding to average threshold voltages of adjacent threshold voltage distributions among the plurality of threshold voltage distributions; generate a reference value by reading read values of the memory cells with the temporary read voltage and decide a standard value corresponding to the temporary read voltage; calculate an error rate based on the reference value and the standard value and set an offset value by reflecting the error rate in a difference between the average threshold voltages of the adjacent threshold voltage distributions; and set a read voltage by applying the offset value to the temporary read voltage.