ROT13 Cipher🔒 100% local
Encode/decode text using ROT13 cipher. Self-inverse: applying twice returns original text.
ROT13 rotates each letter by 13 positions in the alphabet. It's self-inverse: applying ROT13 twice returns the original text. Only letters A-Z/a-z are transformed; numbers and symbols pass through unchanged.
Related Tools
Applies the ROT13 substitution to text: each A-Z or a-z character is shifted 13 places round the alphabet, wrapping at the end, and every other character - digits, punctuation, spaces, accented letters - is left exactly as it was. The same button encodes and decodes, because the shift is its own inverse. Your text is transformed in the page and never leaves it.
How to use it
- Paste the text to scramble (or the scrambled text to read back) into the box.
- Press ROT13 Encode/Decode.
- Read or copy the result. Press the button a second time on the output to return to the original.
Worked example
Attack at dawn! #42becomesNggnpx ng qnja! #42Computed in Node with the same character-by-character shift. The digits, exclamation mark and hash pass through untouched.
Hello WorldbecomesUryyb JbeyqUryyb JbeyqbecomesHello WorldThe same input through the same function decodes, since ROT13 applied twice restores the text.
When to use it
- Hiding the answer to a puzzle or a quiz hint so it does not spoil itself at a glance.
- Obscuring a plot point or a spoiler in a forum post where a reader has to choose to decode it.
- Reading a string you know is ROT13, such as an obfuscated email address in an old page source.
What it does not do
- ROT13 is not encryption and hides nothing from anyone willing to shift the alphabet. Do not use it on anything confidential.
- Only the 52 unaccented Latin letters move. 'cafe' becomes 'pnfr' but 'cafe' with an acute accent leaves the accented letter in place, which can look like a bug in the middle of a word.
- There are no options: no other rotation amounts, no ROT5 for digits, no alphabet to choose from.
- Clear resets the box to the built-in sample text rather than emptying it, unlike most of the other text tools on the site.