computing tools

ROT13 Encoder & Decoder

Apply the reversible ROT13 letter substitution.

Runs locally

Browser-only computing

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Classical ciphers are educational and do not provide modern security.

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One idea, three depths

Choose how deeply to explain ROT13 converter

ROT13 converter: Apply the reversible ROT13 letter substitution.

Age 5Explain it to a 5-year-oldStart with a picture

Imagine replacing letters by a secret rule so a friend who knows the rule can turn the message back again. Apply the reversible ROT13 letter substitution.

Age 15Explain it to a 15-year-oldConnect it to the formula

Apply the reversible ROT13 letter substitution. ROT13 is a fixed Caesar shift of 13 and is not encryption. Change one input or choice at a time and compare the result to see which part of the rule it controls.

CollegeExplain it at college levelState the model precisely

The browser applies the selected hash, encoding, verification, or classical-cipher algorithm locally. ROT13 is a fixed Caesar shift of 13 and is not encryption. Entries and results remain in this browser. Important results should still be checked against the records, standards, or rules that govern the real situation.

How this tool works

ROT13 is a fixed Caesar shift of 13 and is not encryption.

Privacy and limitations

Your entries and results stay in this browser. Check important results against the rules, records or systems that govern your situation.

Supporting sourcesAcademic referencesPrimary standards, textbooks and complete citations

Standards, reading and academic references

Use the calculator as the worked interaction, then consult the primary standards and academic textbooks listed below. MW SysArc links to the original sources; the explanation on this page is original and does not reproduce them.

Introduction to Computer Science

Read the free OpenStax computer science textbook
Cite this book
APA 7
Franchitti, J.-C. (2024). Introduction to computer science. OpenStax. https://openstax.org/books/introduction-computer-science/pages/1-introduction
MLA 9
Franchitti, Jean-Claude. Introduction to Computer Science. OpenStax, 2024, https://openstax.org/books/introduction-computer-science/pages/1-introduction.
Chicago author-date
Franchitti, Jean-Claude. 2024. Introduction to Computer Science. Houston, TX: OpenStax. https://openstax.org/books/introduction-computer-science/pages/1-introduction.

Introduction to Python Programming

Learn how calculations become Python programs
Cite this book
APA 7
Das, U., Lawson, A., Mayfield, C., & Norouzi, N. (2024). Introduction to Python programming. OpenStax. https://openstax.org/books/introduction-python-programming/pages/1-introduction
MLA 9
Das, Udayan, et al. Introduction to Python Programming. OpenStax, 2024, https://openstax.org/books/introduction-python-programming/pages/1-introduction.
Chicago author-date
Das, Udayan, Aubrey Lawson, Chris Mayfield, and Narges Norouzi. 2024. Introduction to Python Programming. Houston, TX: OpenStax. https://openstax.org/books/introduction-python-programming/pages/1-introduction.

OpenStax entries are free to read online. Follow the licence shown on each linked source before redistributing or adapting its content.

Reuse the page responsiblyCite this pageAPA, MLA, Chicago, Harvard, BibTeX and RIS

These formats cite this calculator page itself. They are separate from the academic references above, which support the mathematical method and terminology.

APA 7

MW SysArc. (2026, July 21). ROT13 Encoder & Decoder. MW SysArc Tools. https://computing.mwsysarc.com/rot13-converter

MLA 9

MW SysArc. “ROT13 Encoder & Decoder.” MW SysArc Tools, 21 July 2026, https://computing.mwsysarc.com/rot13-converter. Accessed 4 Sept. 2026.

Chicago 17

MW SysArc. “ROT13 Encoder & Decoder.” MW SysArc Tools. Published July 21, 2026. Accessed September 4, 2026. https://computing.mwsysarc.com/rot13-converter.

Harvard

MW SysArc (2026) ‘ROT13 Encoder & Decoder’, MW SysArc Tools. Published 21 July 2026. Available at: https://computing.mwsysarc.com/rot13-converter (Accessed: 4 September 2026).

BibTeX and RIS records

BibTeX

@misc{mwsysarc_rot13_converter_2026,
  author = {{MW SysArc}},
  title = {ROT13 Encoder & Decoder},
  howpublished = {MW SysArc Tools},
  year = {2026},
  url = {https://computing.mwsysarc.com/rot13-converter},
  note = {Published July 21, 2026; accessed September 4, 2026}
}

RIS

TY  - ELEC
AU  - MW SysArc
TI  - ROT13 Encoder & Decoder
T2  - MW SysArc Tools
PY  - 2026
DA  - 2026-07-21
Y2  - 2026-09-04
UR  - https://computing.mwsysarc.com/rot13-converter
N1  - Published July 21, 2026
ER  -

Clear answers

Frequently asked questions

What does the ROT13 converter do?

Apply the reversible ROT13 letter substitution.

How does the ROT13 converter work?

ROT13 is a fixed Caesar shift of 13 and is not encryption.

What can I learn from the ROT13 converter?

It shows how the entered values or choices produce the result. Change one input at a time to compare outcomes and understand the underlying rule.

Does MW SysArc receive or store what I enter?

No. The calculation runs locally in your browser. MW SysArc does not receive or store your calculation inputs.

How should I use the result?

Use the result as a practical reference. Review the inputs, assumptions and stated limitations before relying on it.

Last reviewed . Calculations tested .

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