A storage device includes one or more nonvolatile memories and a memory controller. The memory controller controls operations of the nonvolatile memories. The memory controller controls the nonvolatile memories differently based on a data amount of write data stored in the nonvolatile memories and/or read data output from the nonvolatile memories according to the operations of the nonvolatile memories during each of a plurality of power supply intervals between a point in time where power is supplied and a point in time where the supplied power is interrupted.