ROT13 shifts every English letter by 13 places, exactly half the alphabet, so applying it twice gives back the original text. ROT47 does the same to every printable ASCII character: letters, digits and symbols. There is also ROT5 for digits and ROT18 for letters and digits at once. Cyrillic is left alone.
Everything runs in your browser — the text goes nowhere
English has 26 letters and 13 is exactly half, so a second pass gives back the original.
ROT47
! … ~ · 94 characters
Every printable ASCII character moves: letters, digits and symbols. Spaces and Cyrillic stay.
A curtain, not a lock
spoilers and answers
Anyone can read ROT13. It hides what should not be seen at a glance: a puzzle answer or a film ending.
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Frequently asked questions
Each English letter is replaced by the one 13 places further on: a becomes n, and n becomes a. The alphabet has 26 letters and 13 is exactly half, so encoding and decoding are the same action. Case is kept, and digits, spaces and punctuation stay where they are: Hello, World turns into Uryyb, Jbeyq.
ROT47 works on every printable ASCII character from ! to ~, ninety-four of them, and a shift of 47 is again half the circle. Letters, digits and symbols all change: Hello, World becomes w6==@[ (@C=5. The space is not part of ROT47 and stays a space. Like ROT13, it is its own inverse, so the same setting decodes.
ROT5 shifts only digits, by five: 1 becomes 6 and 7 becomes 2. ROT18 is ROT13 and ROT5 together, letters by 13 and digits by 5, which hides both words and numbers. Like ROT13, both give back the original when applied a second time. The switch above the box changes the variant and the result updates at once.
No. ROT13 was made for the 26-letter English alphabet and leaves Cyrillic untouched, so Russian text passes through unchanged. For Russian the same idea is the Caesar cipher: a shift of 16 in the 32-letter alphabet without Ё is also exactly half and also undoes itself. The Caesar page can find the shift if you do not know it.
ROT13 does not protect anything, since anyone can read it. It hides what should not be seen at a glance: a puzzle answer, a spoiler, the end of a film. Usenet users did this back in the 1980s, many mail clients and text editors have ROT13 built in, and puzzles and escape games use it as the first and easiest level.
No. The shift is computed in your browser, the text stays on your device and is not written into the page address. Only the Share button creates a link with the text, and the note under it says what goes into that link. Statistics record only that the tool was used, never what was in the box.