An operating method of a nonvolatile memory device including a page buffer array in which a plurality of page buffers are arranged in a matrix form includes counting fail bits stored in the page buffers included in first columns determined based on an operation mode from among a plurality of columns of the page buffer array, and determining whether or not a program has passed with respect to memory cells to which the page buffer array is connected, based on a count result corresponding to a number of the fail bits and a reference count determined based on the operation mode.