ROT13 / ROT47 Encoder / Decoder

How to use this tool

Choose ROT13 or ROT47. ROT13 is selected by default. Choose ROT47 when you also want printable ASCII digits and punctuation transformed.
Type or paste your text. Enter text in the input area. The selected transformation updates the output as you type.
Read or swap the output. The output appears immediately. Both modes are self-inverse, so Swap puts the result back into the input to decode it.
Copy the result. Click the copy button to copy the output to your clipboard.

What are ROT13 and ROT47?

ROT13 ("rotate by 13 places") is a letter-substitution cipher and a fixed-key Caesar cipher. It shifts each uppercase or lowercase English letter 13 places while preserving case. The English alphabet has 26 letters, so A maps to N and N maps back to A. Digits, punctuation, spaces, and other code points pass through unchanged.

ROT47 is another reversible rotation, this time over the 94 printable ASCII characters from ! (code 33) through ~ (code 126). Each character advances 47 positions within that range, wrapping at the end. This changes letters as well as visible punctuation and digits. A regular space (code 32), control characters, and non-ASCII characters remain as they were.

The selector above keeps ROT13 as the default and lets you choose ROT47 when punctuation and digits should also change. Both modes update the result as you type. Their Swap control places the result back into the input, where the same mode restores the starting message.

ROT13 and ROT47 examples

The same sample makes their different character ranges easy to see. ROT13 leaves the comma, space, and exclamation mark untouched. ROT47 changes the comma, letters, and exclamation mark, while leaving the space in place.

Mode	Input	Output
ROT13	`Hello, World!`	`Uryyb, Jbeyq!`
ROT47	`Hello, World!`	`w6==@[ (@C=5P`

When to use each mode

Each transformation is its own inverse: ROT13 applies a total shift of 26 positions after two passes, and ROT47 applies a total shift of 94. Applying either mode twice therefore restores the exact original text, which is why one operation can both encode and decode. Use ROT13 for a familiar letter-only spoiler or puzzle answer; use ROT47 when visible ASCII symbols should be obscured too. Neither changes text into a secure secret. The mappings are fixed and easy to reverse, so do not use these ciphers to protect passwords, personal information, or other confidential data.

Frequently asked questions

What is ROT13?

ROT13 ("rotate by 13 places") is a simple letter substitution cipher. Each letter is replaced by the letter 13 positions after it in the alphabet, wrapping around at Z. Because the English alphabet has 26 letters, applying ROT13 twice always returns the original text.

How is ROT47 different from ROT13?

ROT13 shifts only English letters by 13 places. ROT47 rotates all printable ASCII characters from ! through ~, including digits and punctuation. Both preserve spaces and non-ASCII code points, and both undo themselves when applied twice.

Are ROT13 or ROT47 secure encryption?

Neither provides cryptographic security. They are simple, reversible substitutions for casually obscuring spoilers or puzzle text, not for protecting passwords, personal information, or other secrets.

How is ROT13 different from a Caesar cipher?

ROT13 is a Caesar cipher with a fixed shift of 13. Unlike a general Caesar cipher where you choose any shift from 1–25, ROT13 always uses 13 and is therefore self-inverse.

Which characters change in each mode?

ROT13 changes the English letters a–z and A–Z; digits and punctuation stay the same. ROT47 changes printable ASCII from code 33 (!) through code 126 (~), while spaces, controls, and non-ASCII code points pass through unchanged.

How do I decode a ROT13 or ROT47 result?

Choose the same mode that produced the text and enter the encoded result. Both transforms are self-inverse, so the output decodes it. Swap input and output to see the original text return.