ROT13 Encoder & Decoder
Apply ROT13 to hide or reveal text — the same button does both.
ROT13 is a Caesar cipher with a fixed shift of 13. Because the alphabet has 26 letters, applying it twice returns the original text — so the same button both encodes and decodes. It's used to hide spoilers and puzzle answers, not for real security. Runs in your browser.
Apply ROT13 to any text. ROT13 is a Caesar cipher with a fixed shift of 13, and because the alphabet has 26 letters, running it twice returns the original — so a single button both encodes and decodes. It's the classic way to hide spoilers, puzzle answers and mild jokes in plain sight. Runs entirely in your browser.
How to use the ROT13 Encoder / Decoder
- Type or paste your text.
- Read the ROT13 output instantly.
- Run it again on the output to get back the original.
Frequently asked questions
Why does the same tool encode and decode?
ROT13 shifts letters by 13, exactly half of 26. Applying it a second time shifts another 13, which wraps fully around the alphabet back to the start — so encode and decode are identical operations.
Is ROT13 encryption?
Not in any secure sense — it offers no protection. It's a convention for lightly obscuring text like spoilers so it isn't read by accident.