A nonvolatile memory device includes a first memory stack including first memory cells vertically stacked on each other, a second memory stack including memory cells vertically stacked on each other, and a control logic configured to set a voltage level of a second voltage applied for a second memory operation to one of the second memory cells in the second memory stack based on a first voltage applied to one of the first memory cells in the first memory stack in a first memory operation. The second memory stack is vertically stacked on the first memory stack. Cell characteristics of the one of the first memory cells is determined using the first voltage.