Uses of Hexadecimal (Cambridge (CIE) O Level Computer Science)

Revision Note

Robert Hampton

Written by: Robert Hampton

Reviewed by: James Woodhouse

Uses of Hexadecimal

Why is hexadecimal used?

  • In Computer Science hexadecimal is often preferred when working with large values

  • It takes fewer digits to represent a given value in hexadecimal than in binary

    • 1 hexadecimal digit corresponds 4 bits (one nibble) and can represent 16 unique values (0-F)

  • It is beneficial to use hexadecimal over binary because:

    • The more bits there are in a binary number, the harder it makes for a human to read

    • Numbers with more bits are more prone to errors when being copied

  • Examples of where hexadecimal can be seen:

    • MAC addresses

    • Colour codes

    • URLs

MAC addresses

  • A typical MAC address consists of 12 hexadecimal digits, equivalent to 48 digits in in binary

    • AA:BB:CC:DD:EE:FF

    • 10101010:10111011:11001100:11011101:11101110:11111111

  • Writing down or performing calculations with 48 binary digits makes it very easy to make a mistake

Example of a MAC addresses displayed in a windows command prompt

Colour codes

  • A typical hexadecimal colour code consists of 6 hexadecimal digits, equivalent to 24 digits in binary

    • #66FF33 (green)

    • 01000010:11111111:00110011

Example colour palette with colours and their hexadecimal codes

URL's

  • A URL can only contain standard characters (a-z and A-Z), numbers (0-9) and some special symbols which is enough for basic web browsing

  • If a URL needs to include a character outside of this set, they are converted into a hexadecimal code

  • Hexadecimal codes included in a URL are prefixed with a % sign

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Robert Hampton

Author: Robert Hampton

Expertise: Computer Science Content Creator

Rob has over 16 years' experience teaching Computer Science and ICT at KS3 & GCSE levels. Rob has demonstrated strong leadership as Head of Department since 2012 and previously supported teacher development as a Specialist Leader of Education, empowering departments to excel in Computer Science. Beyond his tech expertise, Robert embraces the virtual world as an avid gamer, conquering digital battlefields when he's not coding.

James Woodhouse

Author: James Woodhouse

Expertise: Computer Science

James graduated from the University of Sunderland with a degree in ICT and Computing education. He has over 14 years of experience both teaching and leading in Computer Science, specialising in teaching GCSE and A-level. James has held various leadership roles, including Head of Computer Science and coordinator positions for Key Stage 3 and Key Stage 4. James has a keen interest in networking security and technologies aimed at preventing security breaches.