I don't know, but it will hold over 12 adult size books easily. 120 hours of books, probably more. That's a lot of songs. You keep all your songs on your computer. Hook your nano up to the computer to put the songs you want on for the present, and take off the ones you don't. I listen to books a lot during the day, and at night. I figure I could listen to the books on my computer easily for over a month, without a repeat. It depends on the length of the song, that sort of thing.