ROT13 Encoder & Decoder | Caesar Cipher Tool
Encode or decode text using ROT13—a simple letter substitution cipher that replaces each letter with the letter 13 positions ahead. Perfect for hiding spoilers, puzzles, and basic obfuscation. 100% browser-based.
How to Use This Tool
- 1
Paste or type your text into the input field.
- 2
Click Encode to apply ROT13 (or Decode—it works the same way).
- 3
Copy the result or use Swap to reverse input/output.
- 4
ROT13 is symmetric: applying it twice returns the original text.
- 5
Perfect for hiding spoilers, puzzle creation, and simple text obfuscation.
Use Cases & Examples
Spoiler Hiding
Hide movie endings, book plots, or game secrets without permanent encryption.
Puzzle & Game Creation
Create simple encoded puzzles, treasure hunts, or riddles.
Text Obfuscation
Obscure text temporarily to prevent accidental reading.
Education & Cryptography Learning
Learn about classic ciphers and substitution encryption.
How ROT13 Works
ROT13 is a Caesar cipher that shifts each letter by 13 positions in the English alphabet.
Because there are 26 letters, applying ROT13 twice returns the original text (symmetric).
Only letters (A-Z, a-z) are affected; numbers, punctuation, and symbols remain unchanged.
Commonly used to hide spoilers in forums, newsgroups, and puzzle communities.
Frequently Asked Questions
Q.What is ROT13?
A. ROT13 ("rotate by 13") is a Caesar cipher that shifts each letter 13 positions in the alphabet. A becomes N, B becomes O, etc.
Q.Is there a difference between encode and decode?
A. No. ROT13 is symmetric—encoding and decoding use the same operation. Click Encode or Decode; both work the same way.
Q.What characters does ROT13 affect?
A. Only letters (A-Z, a-z) are rotated. Numbers, spaces, punctuation, and special characters remain unchanged.
Q.Is ROT13 secure?
A. No. ROT13 is trivial to break and should only be used for hiding spoilers or simple obfuscation, not for security.
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