ROT13 Encoder / Decoder
Apply ROT13 cipher to text
ROT13 Encoder / Decoder is a free online tool from BrowserUtils that apply rot13 cipher to text. It runs entirely in your browser — your data never leaves your device. No account required.
ROT13 is its own inverse — encoding and decoding are the same operation.
How to use ROT13 Encoder / Decoder
- 1 Paste or type your input into the editor above.
- 2 The tool processes your data instantly — right in your browser, with nothing sent to a server.
- 3 Copy the result with one click or continue editing your input.
About ROT13 Encoder / Decoder
Free online ROT13 encoder and decoder. Apply the ROT13 substitution cipher to shift letters by 13 positions. This tool runs entirely in your browser — your data is never sent to a server. Just paste your input, get instant results, and copy with one click. No sign-up or installation required.
ROT13 Encoder / Decoder specs
- Runtime
- 100% client-side (browser)
- Built on
- TextEncoder, TextDecoder, btoa/atob, and encodeURIComponent — all Web Platform APIs
- Cost
- Free — no account, no rate limits, no usage caps
- Browser support
- Chrome 90+, Firefox 88+, Safari 14+, Edge 90+
- Part of
- 299 developer tools on BrowserUtils (100% client-side)
Questions
What is ROT13?
ROT13 is a simple substitution cipher that shifts each letter 13 positions in the alphabet. Since the alphabet has 26 letters, applying ROT13 twice returns the original text.
Is ROT13 secure?
No. ROT13 provides no cryptographic security. It is used to obscure text (e.g., spoilers) rather than to protect secrets.
Does ROT13 affect numbers and special characters?
No, ROT13 only shifts the 26 English letters. Numbers, spaces, punctuation, and special characters remain unchanged.
How is ROT13 different from the Caesar cipher?
ROT13 is a specific case of the Caesar cipher with a fixed shift of 13. The Caesar cipher allows any shift value from 1 to 25.
Can I use ROT13 to hide spoilers in text?
Yes, ROT13 is commonly used on forums and social media to obscure spoilers. Readers who want to see the content can decode it, while others are not inadvertently spoiled.
Does ROT13 work with non-English text?
ROT13 only shifts the 26 standard English letters (A-Z). Characters from other alphabets, accented letters, and non-Latin scripts pass through unchanged.
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