How to use this ROT13 decoder
- Paste your text in the box above — ROT13 or plain English, it does not matter.
- The result updates instantly. Use Swap to put the result back into the input.
- Copy the result with the Copy button.
What is ROT13?
ROT13 is a Caesar cipher with a shift of 13. Each letter is replaced by the letter 13 places after it in the alphabet: A becomes N, B becomes O, H becomes U, and so on. So HELLO becomes URYYB, and URYYB becomes HELLO again. Because the alphabet has 26 letters, shifting by 13 twice brings you back to the start — which is why a ROT13 decoder and a ROT13 encoder are the same tool.
ROT13 is mostly used to hide spoilers, puzzle answers, jokes and solutions online. A forum post might say “ROT13: Gur raqvat jnf n qernz” so that readers only learn the ending if they choose to decode it. It also shows up in puzzle hunts, escape rooms and CTF challenges, where spotting ROT13 is one of the first skills to learn.
Examples — decode ROT13
- GUR CNFFJBEQ VF FHPPRFF → THE PASSWORD IS SUCCESS
- URYYB JBEYQ → HELLO WORLD
- V YBIR LBH → I LOVE YOU
- QB LBH TRG GUVF ZRFFNTR? → DO YOU GET THIS MESSAGE?
Frequently asked questions
What is ROT13?
ROT13 is a Caesar cipher with a shift of 13. Each letter is replaced by the letter 13 places after it in the alphabet: A becomes N, B becomes O, and so on.
How do I decode ROT13?
Apply ROT13 again. Because the alphabet has 26 letters, shifting by 13 twice returns the original text. Paste the ROT13 text above and this tool decodes it instantly.
What is ROT13 used for?
Hiding spoilers, puzzle answers, jokes, and solutions online so readers only see them if they choose to decode them. It also appears in puzzle hunts and CTF challenges.
Is ROT13 real encryption?
No. ROT13 has only one key and anyone can reverse it in seconds. It hides text from casual readers; it does not protect private information.
How is ROT13 different from the Caesar cipher?
ROT13 IS a Caesar cipher — the special case with shift 13. Other Caesar shifts need a different key to decode, but ROT13 decodes with the same operation.
Related tools
Caesar Cipher Decoder — decode any Caesar shift, not just 13, with brute force over all 25 shifts. Atbash Cipher Decoder — the reversed-alphabet cipher. Vigenère Cipher Decoder — the polyalphabetic upgrade that finally beat simple shift ciphers.