A memory system includes a nonvolatile memory and a memory controller. The memory controller determines a read voltage for first data encoded by a first encoding scheme, by generating a first histogram indicating the number of memory cells for each threshold voltage, and estimating the read voltage using: (a) the first histogram that is corrected based on a first parameter of the first encoding scheme, and a second parameter of a second encoding scheme, and an estimation function for estimating a read voltage for second data encoded by the second encoding scheme, or (b) the uncorrected first histogram, and the estimation function that is corrected based on the first and second parameters, or (c) the first histogram after partial correction based on the first and second parameters, and the estimation function after partial correction based on the first and second parameters.