- 1Choose file
- 2Adjust
- 3Download
ROT13 & Caesar Cipher Encoder online, free
Encode and decode text using ROT13, ROT5, ROT47, and custom Caesar shift ciphers instantaneously.
- Runs in your browser — no upload
- Free, no sign-up, no watermark
- TXT
How to use ROT13 & Caesar Cipher Encoder · ROT13 & Caesar Cipher Encoder — frequently asked questions
How to use ROT13 & Caesar Cipher Encoder
- 1
Add your TXT file
Drop a file on the page, paste it, or click Select Files. Nothing is uploaded — it opens straight in your browser.
- 2
Fine-tune the settings
Set cipher variant in the Fine-tune panel, or keep the defaults — they suit most files.
- 3
Run ROT13 & Caesar Cipher Encoder
Press the start button. Processing happens on your device, usually in seconds.
- 4
Download the result
Save the finished file, or continue with another tool without downloading in between.
What ROT13 & Caesar Cipher Encoder can do
- Cipher Variant: rot13, rot5, rot47 and caesar
- Private by design — files are processed in your browser and never uploaded
- Free with no sign-up, no watermark and no daily limit
Common tasks
ROT13 & Caesar Cipher Encoder — frequently asked questions
What is a ROT13 cipher?
ROT13 ("rotate by 13 places") is a simple substitution cipher that replaces each letter with the 13th letter after it in the English alphabet. Because the English alphabet has 26 letters, applying ROT13 twice restores the original text.
What is the difference between ROT13, ROT5, and ROT47?
ROT13 rotates alphabetical characters (A-Z, a-z). ROT5 rotates numeric digits (0-9 by 5 positions). ROT47 rotates all standard ASCII printable characters (from ASCII 33 `!` to 126 `~` by 47 positions).
What is a Caesar cipher?
The Caesar cipher is an ancient encryption technique where each letter in the plaintext is shifted by a fixed number of positions down the alphabet. ROT13 is simply a Caesar cipher with a shift of 13.
Is ROT13 secure for confidential information?
No. ROT13 provides no cryptographic security and is easily decoded. It is primarily used on online forums to obscure spoilers, puzzle answers, and offensive content from casual reading.
Does ROT13 affect numbers and punctuation?
Standard ROT13 only modifies English letters (A-Z and a-z). Spaces, punctuation, and numbers remain unchanged unless you choose the ROT47 or ROT5 variants.
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