A storage device includes a nonvolatile memory and a controller. The controller is configured to generate coded data based on write data and an error correction code generated from the write data, determine whether or not to invert each bit of the coded data, based on a logical page position of the nonvolatile memory in which the write data are to be written and a value “0” or “1” of bits that are more populated in the coded data than bits having the other value of “1” and “0”, invert each bit of the coded data upon determining to invert, and write the non-inverted or inverted coded data into the logical page position of the nonvolatile memory. The logical page position is one of logical page positions including a lower page and an upper page.