ROT13 Converter
Encode and decode ROT13 text instantly, with ROT5, ROT18 and ROT47 variants built in.
Puzzle toy, not encryption. ROT13 is a fixed letter substitution with no key, so anyone can undo it in seconds. Use it for spoilers, forum puzzles, geocaching hints and CTF warm-ups — never for passwords or anything that needs to stay private.
ROT13 alphabet chart
- A ↔ N
- B ↔ O
- C ↔ P
- D ↔ Q
- E ↔ R
- F ↔ S
- G ↔ T
- H ↔ U
- I ↔ V
- J ↔ W
- K ↔ X
- L ↔ Y
- M ↔ Z
Each letter moves 13 places along the 26-letter alphabet and wraps around, so the mapping is
symmetric: A ↔ N, B ↔ O, and so on. Case is preserved and
everything that is not a letter is left untouched.
How it works
ROT13 (“rotate by 13”) is the Caesar cipher with a shift of 13. Every letter is replaced by
the one 13 positions later in the alphabet, wrapping from Z back to A, so
Hello, World! becomes Uryyb, Jbeyq!. Because 13 is exactly half of
26, encoding and decoding are the same operation — there is one button, not two, and pressing
Use result as input returns your original text. Upper and lower case are kept
as they are, and digits, spaces, punctuation, accents and emoji pass through unchanged.
Three related variants are included. ROT5 rotates the digits 0–9 by five
(2026 → 7571), ROT18 applies ROT13 to letters and
ROT5 to digits at the same time, and ROT47 rotates all 94 printable ASCII
characters (! through ~) by 47, turning
Hello World! into w6==@ (@C=5P. All four are self-inverse.
These are classical puzzle ciphers used for hiding spoilers and answers in plain sight, not security tools: there is no key and the transformation is public, so treat anything you encode as readable by anyone. The conversion runs entirely in your browser with JavaScript — your text is never uploaded, stored or logged.
Frequently asked questions
What is ROT13?
ROT13 is the Caesar cipher with a shift of 13: every letter is replaced by the one 13 places later in the alphabet, wrapping Z back to A. Because 13 is half of 26, encoding and decoding are the same operation, so "Hello, World!" becomes "Uryyb, Jbeyq!" and running it again returns the original text.
How do you decode ROT13 text?
Paste the encoded text into the input box and read the result — ROT13 is its own inverse, so the same conversion decodes it. There is no separate decode button and no key to enter. Digits, punctuation, spaces and emoji pass through unchanged, and letter case is preserved.
Is ROT13 secure encryption?
No. ROT13 is a puzzle and spoiler-hiding toy with no key at all, so anyone can reverse it instantly. It is fine for forum spoilers, geocaching hints and CTF warm-ups, but never use it for passwords or private data — use real encryption such as AES for that.