HesapHanem

ROT47 Cipher

Transform text with the self-inverse ROT47 cipher.

How it is calculated

ROT47 shifts every printable ASCII character with code 33 to 126 (94 characters: letters, digits and punctuation) forward by 47 places, wrapping around at the end: new = 33 + ((code − 33 + 47) mod 94). Spaces, line breaks and any character outside that range, such as accented letters or emoji, are copied through unchanged.

Since 47 is exactly half of 94, applying the cipher twice returns the original text, so the same operation both encodes and decodes. There is no key and no secrecy: it only hides text from a casual glance. The tool works byte by byte, so non-ASCII characters are left as they are.

Worked example

Take Hello, World!. The letter H has code 72; 72 − 33 = 39, 39 + 47 = 86, and 33 + 86 = 119, which is w. The letter e (101) becomes 101 − 33 + 47 = 115, 115 mod 94 = 21, 33 + 21 = 54, which is 6. The comma and exclamation mark are also rotated, while the space is kept. The full result is w6==@[ (@C=5P. Running that through the tool again gives back the original.

Try this example →

Common mistakes

  • Treating ROT47 as encryption. Anyone can reverse it in seconds with no key, so never use it for passwords or private data.
  • Expecting it to work like ROT13. ROT13 only moves letters and leaves digits and punctuation, so ROT13 text and ROT47 text do not decode each other.
  • Expecting accented letters (ç, ö, ğ) or emoji to be scrambled. Only the 94 printable ASCII characters change.
  • Trying to decode a message that was changed by an email client or editor, for example with curly quotes replacing straight ones. Any changed character breaks the result.

About this calculator

This calculator encodes or decodes text with ROT47, a Caesar-style cipher that rotates all 94 printable ASCII characters (codes 33-126, covering letters, digits, and symbols) by 47 positions instead of just rotating the 26-letter alphabet like classic ROT13.

Because ROT47 is self-inverse — applying it twice returns the original text — developers and forum users use it to casually obscure spoilers, code snippets, or puzzle answers from a quick glance without needing a decode step.

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Comments (1)

  • Editorial team

    Because spaces and line breaks pass through untouched, the scrambled output keeps the same word lengths and layout as the original, which is a giveaway if someone wants to guess a short phrase. Digits and punctuation do change, so a URL or a snippet of code comes out looking unrecognisable. It suits spoiler tags, not secrets. What kind of text do you usually need to hide, spoilers, puzzle answers or something else?

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