How much memory does a 6 hour audio book use?

Since a 650MB CD holds 74 minutes of audio, a 6 hour book requires about 3.2GB when talking about an audio book on a CD. An audiobook downloaded from the internet, such as through iTunes can be much smaller. A five out book in low quality is around 20MB while at high quality the file is usually around 70MB. This difference is because a CD uses a much higher sampling rate than most audio formats used on computers.