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Fetch-Decode-Execute Cycle - GCSE Computer Science Definition

Reviewed by: Robert Hampton

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What is the fetch-decode-execute cycle?

In GCSE Computer Science, the fetch-decode-execute (FDE) cycle, also known as the fetch-execute cycle, is defined as the cycle that the central processing unit (CPU) runs through billions of times per second to make a computer work.

Diagram of a CPU with arrows illustrating the fetch-decode-execute cycle, showing how processors handle instructions.
Illustration of the fetch-decode-execute cycle

The four main steps of the fetch-decode-execute cycle are:

  • An instruction or data is fetched from memory

  • The instruction is decoded 

  • The instruction is executed

  • The cycle repeats billions of times per second

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Robert Hampton

Reviewer: 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.

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