Types

• DVDs can be single-layer or dual layer. A single-layer DVD can hold 4.7 GB of data; a dual-layer DVD holds 8.5 GB. Single- and dual-layer Blu-ray DVDs hold 25 GB and 50 GB, respectively.
  
  

Comparison

• CDs only hold 700 MB of data. A single-layer DVD holds over six and a half times that amount.
  
  

Media

• CDs and DVDs can hold varying types of media, such as music and video. The number of minutes they can store depends on the format of that media.
  
  

Capacity

• CDs can hold about 80 minutes of music and up to 74 minutes of VHS-quality video. A single-layer DVD can hold about 15 hours of VHS-quality video or two hours of high-quality video, and a single-layer Blu-ray DVD can hold over 4.5 hours of high-definition (HD) video.
  
  

Fun Fact

• A CD can hold enough music to contain Beethoven's entire ninth symphony.