A nonvolatile memory device includes a memory cell region including a first metal pad, and a peripheral circuit region including a second metal pad and vertically connected to the memory cell region by the first metal pad and the second metal pad. The memory cell region includes a first memory stack comprising first memory cells vertically stacked on each other, and a second memory stack comprising second memory cells vertically stacked on each other. The peripheral circuit region includes a control logic for setting a voltage level of a second voltage applied for a second memory operation to a second memory cell of the second memory cells based on a first voltage applied to a first memory cell of the first memory cells in a first memory operation. Cell characteristics of the first memory cell are determined using the first voltage.