ROT13 Decoder
Decode ROT13 text (a fixed 13-letter shift).
Runs in your browser Your input never leaves your device.
Report a problem with this tool
About this tool
Decodes text that was scrambled with ROT13, a simple cipher that replaces each letter with the one 13 places later in the alphabet. Because the alphabet has 26 letters, applying ROT13 twice returns the original, so decoding is the same operation as encoding. Only the letters A-Z and a-z are changed, with their case kept; digits, punctuation, spaces and accented letters stay as they are. ROT13 is not real encryption and offers no security. It is used to hide spoilers or puzzle answers. Despite the idea of other rotations, this tool applies the fixed shift of 13 only. It runs in your browser.
How to use it
- Paste the ROT13 text.
- Read the decoded text in the output.
- Copy it if needed.
Example
Uryyb, Jbeyq!
Hello, World!
ROT13 in Linux and other tools
ROT13 is simple to apply without a website. On Linux or macOS, tr maps each letter to the one 13 places on:
echo 'Uryyb, Jbeyq!' | tr 'A-Za-z' 'N-ZA-Mn-za-m'
# Python
import codecs
codecs.decode('Uryyb, Jbeyq!', 'rot_13')
# Vim: g?? applies ROT13 to the current line The ROT13 letter table
Each letter in the first half of the alphabet swaps with the matching letter in the second half, and the swap works both ways:
A-N, B-O, C-P, D-Q, E-R, F-S, G-T, H-U, I-V, J-W, K-X, L-Y, M-Z.
Lowercase letters follow the same table.
How to spot ROT13 text
ROT13 text looks like words, with the same lengths, spaces and punctuation as normal text, but the letters make no sense. Short common words give it away: gur is the, naq is and, bs is of, gb is to and vf is is. If you see those, the text is very likely ROT13. If the words are as scrambled but these patterns do not appear, it may use a different shift or a different cipher.
ROT13, Caesar and ROT47
- Caesar cipher
- Shifts letters by any fixed amount. ROT13 is the Caesar cipher with a shift of 13, the one shift where encoding and decoding are the same.
- ROT47
- Rotates all printable ASCII characters from ! to ~ by 47, so digits and punctuation change too. This tool does not decode ROT47.
- ROT5
- Rotates digits only, 0-9 by 5. This tool leaves digits alone.
Common problems
- Text is still unreadable
- It may use another rotation, such as ROT-5 or a different cipher. This tool shifts by 13 only.
- Numbers or accents did not change
- Only unaccented English letters are rotated.
- Using it to protect data
- ROT13 is trivially reversible. Use a real encryption tool for sensitive content.
Frequently asked questions
Is the ROT13 decoder different from the encoder?
No. Shifting by 13 twice brings each letter back, so the ROT13 Encoder and this decoder do the same thing. Either one works in both directions.
Why is ROT13 used at all?
To hide text from a casual glance, such as spoilers, puzzle answers or jokes, while letting anyone who wants to read it decode it in seconds.