ROT47 Encoder & Decoder

ROT47 rotates every visible ASCII character by 47 places, so unlike ROT13 it also scrambles digits and punctuation. Paste text and see the transformed result instantly; run ROT47 again on the output to get your original back, because the cipher is its own inverse. Everything runs locally.

How to use the ROT47 Encoder & Decoder

Type or paste text into the input box and the ROT47 result appears below as you type. Because ROT47 with a rotation of 47 is its own inverse, the same operation both encodes and decodes — to recover the original, press Send output to input and you will see your starting text return. Copy output places the result on your clipboard.

The Rotation slider lets you change the shift from the default 47 to any value between 1 and 93, turning the tool into a general printable-ASCII Caesar cipher. Only the 94 visible ASCII characters (codes 33 through 126) are rotated; spaces, tabs, and newlines are left untouched so the shape of your text is preserved, and any non-ASCII characters such as accented letters or emoji pass through unchanged. With the slider at 47, encode and decode are identical; with any other value, decode by setting the slider to 94 minus your encode value.

It all runs in your browser with no network calls, so it is instant, works offline, and nothing you type is sent anywhere.

How ROT47 works and where it fits

ROT47 is a simple letter-substitution cipher and a direct descendant of ROT13. Where ROT13 rotates only the 26 letters of the alphabet by 13 places, ROT47 operates on the 94 printable ASCII characters — the block from ! (code 33) through ~ (code 126) — and rotates each by 47. Because 47 is exactly half of 94, applying ROT47 twice returns every character to its starting point, which makes the cipher its own inverse: one function both scrambles and unscrambles. This self-inverse property is the same neat trick that makes ROT13 popular, extended to a larger character set.

The practical difference from ROT13 is coverage. ROT13 leaves digits and punctuation visible — "Meet at 5pm!" still shows the 5, the p, and the exclamation mark in clear form. ROT47 rotates those too, so the same text becomes an opaque-looking jumble of symbols. That is why ROT47 is often preferred for lightly obscuring text that contains numbers, URLs, or code: a ROT13'd email address still reveals its @ and dots, whereas a ROT47'd one looks like noise. The rotation wraps around within the 94-character window, so a character near the end of the range, like ~, lands back near the start.

It is essential to be clear about what ROT47 is not: it is not encryption and provides no security. There is no key — the shift is fixed and public — so anyone can reverse it instantly, exactly as this tool does. Its legitimate uses are the same as ROT13's: hiding spoilers, puzzle answers, or offensive words from casual view; obfuscating strings just enough that they are not readable at a glance; and teaching the mechanics of substitution ciphers and modular arithmetic. ROT47 appears in puzzle hunts and CTF challenges precisely because it looks more cryptic than ROT13 while being just as trivial to undo once you recognize it. For anything that actually needs to stay secret, a real cipher with a key is required.

Common use cases

  • Hiding spoilers. Obscure puzzle answers, plot details, or punchlines so they are not readable at a glance.
  • Light obfuscation. Scramble text containing numbers and punctuation that ROT13 would leave exposed.
  • Puzzles and CTFs. Encode or recognize and decode ROT47 strings in challenges.
  • Learning. Explore substitution ciphers and modular rotation over a full character range.

Frequently asked questions

How is ROT47 different from ROT13?
ROT13 rotates only the 26 letters; ROT47 rotates all 94 printable ASCII characters, so digits and punctuation are scrambled too. That makes ROT47 output look fully cryptic rather than partially readable.

Is ROT47 secure?
No. It is not encryption — there is no key and the shift is public, so anyone can reverse it instantly. Use it only for casual obfuscation, spoilers, or puzzles, never to protect real secrets.

How do I decode ROT47?
With the default rotation of 47, run ROT47 again — it is its own inverse. The Send output to input button does exactly that. For a custom rotation N, decode by using 94 minus N.

What happens to spaces and emoji?
Only the printable ASCII range (codes 33-126) is rotated. Spaces, tabs, and newlines stay put, and non-ASCII characters like accented letters or emoji pass through unchanged.