ROT13 Encoder
Encode and decode ROT13 text instantly. Because ROT13 is its own inverse, you just paste your text and convert — the same button both scrambles and unscrambles. Free, private and processed entirely in your browser.
Tip: ROT13 is symmetric — applying it twice returns the original text, so the same conversion both encodes and decodes.
How to use the ROT13 encoder
- Enter your text. Type or paste the message, spoiler or comment you want to convert into the text box.
- Read the result. The ROT13 output appears instantly below and updates as you type — no button press needed.
- Encode or decode the same way. ROT13 is its own inverse, so run scrambled text back through the tool to reveal the original, then copy it with one click.
About this tool
ROT13 (“rotate by 13 places”) is a special case of the Caesar cipher that shifts each letter 13 positions through the 26-letter alphabet. Since 13 is exactly half of 26, applying ROT13 a second time returns the original letter — which is why a single operation both encodes and decodes. It has long been used on forums and Usenet to hide spoilers, punchlines and puzzle answers so that readers must make a deliberate choice to reveal them. Enable the optional ROT5 setting to rotate digits by five as well, a combination often called ROT18.
ROT13 offers no real security whatsoever — it is a reversible obfuscation, not encryption, and anyone can decode it in an instant. Its value is in lightly concealing text from casual view, not in protecting secrets. This tool converts your text locally in your browser, so nothing you type is ever uploaded, logged or stored.
Frequently asked questions
How do I decode ROT13 text?
Just paste the ROT13 text into the box. Because ROT13 is its own inverse, converting encoded text runs it straight back to the original — the same operation encodes and decodes.
What does the ROT5 option do?
It rotates the digits 0–9 by five in addition to rotating letters by 13, so 0 becomes 5, 1 becomes 6, and so on. This combined scheme is sometimes called ROT18 and is also its own inverse.
Is ROT13 secure enough to protect passwords?
No. ROT13 is a simple letter-substitution trick with no key and is trivially reversible. Use it only to hide spoilers or lightly obscure text, never to protect anything sensitive.
Does it change symbols, spaces or line breaks?
No. Only the letters A–Z (and digits when ROT5 is enabled) are rotated. Spaces, punctuation, symbols and line breaks are left exactly as they are, and letter case is preserved.