ROT13 Encoder & Decoder

Encode and decode ROT13 instantly

The ROT13 tool applies the classic ROT13 letter-substitution cipher to your text — and because ROT13 is its own inverse, the very same operation also decodes it. Type or paste your text and the result appears instantly, ready to copy. Everything runs in your browser, so it is fast and private.

What is ROT13?

ROT13 ("rotate by 13 places") replaces each letter with the one 13 positions later in the alphabet. Since the English alphabet has 26 letters, rotating by 13 twice returns the original — which is why encoding and decoding are identical. A becomes N, B becomes O, and so on. Numbers, punctuation, and spaces are left untouched.

What ROT13 is for

ROT13 is not encryption — it provides no security at all and is trivially reversible. Its real purpose is to lightly obscure text so it is not readable at a glance: hiding spoilers, puzzle answers, joke punchlines, or potentially offensive words in online forums. Readers who want to see the hidden text simply run it back through ROT13.

How to use it

1. Type or paste your text.
2. The ROT13 result appears instantly — encoding and decoding are the same operation.
3. Click Copy to grab the result, or Swap to feed it back in.

ROT13 examples

Plain	ROT13
Hello	Uryyb
spoiler	fcbvyre
Tool Central	Gbby Prageny

A piece of internet history

ROT13 has been a Usenet and forum convention for decades, precisely because it is simple and self-reversing. It remains a fun introduction to substitution ciphers and a handy way to hide text in plain sight — just never mistake it for a security measure.

Private and free

All processing happens in your browser. Nothing is uploaded or stored, and there are no limits — use it as much as you like, free.