What Is This?

This is an interpreter for the OCR exam reference language (OCR ERL).

OCR ERL is similar to pseudocode - an idealised programming language used in the latest OCR Computer Science exam syllabus. You can use this site to test out your OCR ERL programs and see how they would actually run.

OCR ERL is designed by and owned by OCR and forms part of their J277 Computer Science specification.

This site and all code is (c) John Williams, 2024, all rights reserved.


  • Line by line debugging (use debug in the menu)
  • Multiline expressions using brackets
  • Multiline strings
  • Stores project in the URL to allow easy sharing (can be turned off for large projects for speed)
  • Provides exact line numbers and extensive details of errors
  • Detects division by zero and raising negative numbers by fractional powers
  • Support for a-level OOP (classes etc). Use the a-level toggle at the top of the page to enable this
  • Provides corrections for common mistakes such as missing keywords, brackets and misspelt operators


This site is provided 'as is' without any representation or endorsement made, and without warranty of any kind whether express or implied.

Found any problems? Let me know at john@examreferencelanguage.co.uk.