Free ROT13 Encoder & Decoder
The ROT13 tool encodes or decodes text with the ROT13 cipher — a simple letter rotation by 13 places. Because ROT13 is symmetric, the same operation both encodes and decodes.
ROT13 is a Caesar shift of 13, so the Caesar Cipher covers every other shift. For anything with a real key, the Vigenère Cipher is the natural next step.
How to use the ROT13 Cipher
- 1 Paste the text you want to transform.
- 2 The output updates instantly — ROT13 is its own inverse, so the same action encodes and decodes.
- 3 Copy the transformed text.
- 4 Paste it back in to confirm it returns to the original.
How to Use
Type text and click Apply. Useful for hiding spoilers in plain sight. Note: ROT13 is not real encryption.
- Rotates letters 13 places
- Same action encodes and decodes
- Leaves digits and symbols unchanged
Frequently asked questions
Is ROT13 encryption?
No — it is a substitution with no key at all, so anyone who recognises it can read it. Its value is that it is self-inverse and trivially reversible, which makes it a convenient way to hide spoilers, puzzle answers or punchlines behind a deliberate extra step.
Why does it leave numbers and punctuation alone?
Because ROT13 only rotates the 26 letters, shifting each by 13 positions. Digits, spaces and symbols have no rotation defined, so they pass through unchanged. That is why encoded text still looks like text rather than gibberish.
What happens to accented characters?
They are left as they are, since ROT13 is defined on the basic Latin alphabet only. Accents, Cyrillic and other scripts pass through untouched — so a ROT13 of a French sentence will only mangle its unaccented letters.
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