• ASCII and Unicode are both methods used to represent text within a computer


  • American Standard Code for Information Interchange
    • The ASCII system was introduced to ensure that all computers use the same binary patterns to represent the computers character set.
    • ASCII gives each character a unique number that can easily be changed into a binary pattern.
      • e.g. A = 65 = 1000001
    • The ASCII system standardises text files making them more compatible with a wider range of computer systems.
    • ASCII is a 7-bit system which enables 128 binary patterns to be available to represent 128 different characters.
    • 32 of these binary patterns are set aside for control characters, e.g. cursor keys.
  • Extended ASCII
    • This system is an 8-bit system and allows the system to store up to 256 different characters.


  • Unicode is a 16-bit system, supporting 65,636 different characters.
  • Unicode is used in countries like Japan, because of the number of characters in their alphabet.

Advantages of Unicode

  • Unicode is a 16-bit system which can support many more characters than ASCII.
  • The first 128 characters are the same as the ASCII system making it compatable.
  • There are 6400 characters set aside for the user or software.
  • There are still characters which have not been defined yet, future-proofing the system.

Disadvantage of Unicode

  • Unicode files are very large because it takes 2 bytes to store each character.


  • Unicode uses 16 bits to represent more characters than ASCII which uses 7
  • Unicode covers every character in every alphabet and is future-proof
  • Unicode is compatible with ASCII, (legacy systems still work)
  • Unicode requires more storage capacity than ASCII

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This page has been edited 5 times. The last modification was made by - cosidesk cosidesk on Sep 5, 2012 4:59 pm