A method for managing data in a storage device includes: receiving a logical page from a host and calculating an actual time stamp of the logical page; finding a block of the storage device in which the logical page is stored and detecting a time stamp of the block and a page offset of the logical page stored in the block; calculating an approximate time stamp of the logical page stored in the block using the time stamp of the block and the page offset; and determining that the logical page is in a first state if the difference between the actual time stamp and the approximate time stamp is smaller than a threshold value, and determining that the logical page is in a second state different from the first state if the difference between the actual time stamp and the approximate time stamp is larger than the threshold value.