# ROT13 Cipher

Encode and decode text using ROT13 substitution cipher (rotates letters by 13 positions)

> Canonical page: https://elysiatools.com/en/tools/rot13-cipher

- **Category:** Format Conversion

- **Keywords:** rot13, cipher, encode, decode, encrypt, decrypt, substitution, rotation

## Overview

The ROT13 Cipher tool allows you to quickly encode and decode text by shifting each letter 13 positions through the alphabet. Because the alphabet has 26 letters, applying the ROT13 substitution twice returns the original text, making it a simple and effective method for basic text obfuscation.

## Inputs

- **Input Text** (textarea): Enter text to encode or decode...
- **Operation** (select)

## When to use

- Obfuscating spoilers in online forums or social media comments.
- Hiding text from casual observation in casual digital communication.
- Quickly reversing ROT13-encoded strings found in puzzles or CTF challenges.

## How it works

- Enter your target text into the input field.
- Select 'Encode' to shift letters by 13 positions or 'Decode' to reverse the process.
- View the transformed output instantly in the results area.

## Use cases

- Hiding plot spoilers in community discussion threads.
- Solving basic substitution puzzles in online games.
- Obfuscating text strings in non-critical development environments.

## Frequently asked questions

### What is ROT13?

ROT13 is a simple substitution cipher that replaces a letter with the 13th letter after it in the alphabet.

### Is ROT13 secure for sensitive data?

No. ROT13 is not a secure encryption method and should only be used for simple obfuscation, such as hiding spoilers.

### Does this tool affect numbers or symbols?

No, the ROT13 algorithm only affects alphabetical characters; numbers and symbols remain unchanged.

### Why does encoding and decoding use the same operation?

Because there are 26 letters in the alphabet, shifting by 13 twice returns the original character.

### Is the tool case-sensitive?

Yes, the tool preserves the original casing of your input text while performing the rotation.

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## Samples

- [Copyright-Free MP3 Audio Samples](https://elysiatools.com/en/samples/mp3-samples): Collection of royalty-free audio samples for testing and development purposes including nature sounds, meditation music, and ambient audio
- [Hex/Unicode Encoding Format Samples](https://elysiatools.com/en/samples/text-hex-unicode-formats): Examples of hex (\xXX) and unicode (\uXXXX) escape sequence encoding formats
- [Android Image Processing Java Samples](https://elysiatools.com/en/samples/android-image-processing-java): Android Java image processing examples including reading/saving images, scaling, and format conversion
- [Android Image Processing Kotlin Samples](https://elysiatools.com/en/samples/android-image-processing-kotlin): Android Kotlin image processing examples including reading/saving images, scaling, and format conversion

## Related content

- [Classical and Modern Cipher Tools](https://elysiatools.com/en/hubs/classical-and-modern-cipher-tools): Practice safe educational and CTF cipher workflows by comparing reversible classical transformations with modern encryption and recording their security limits.