ROT13 Cipher
Encrypt or decrypt text with Caesar cipher, ROT13, or Atbash. Works instantly on any shift.
Free & unlimited
Cipher
Mode
Shift
13 (ROT13)125
Quick shifts
Input
Result
Result appears here as you type.
All processing happens in your browser. No data is sent to any server.
About this tool
- 1
Enter your text
Type or paste the message you want to encrypt or decrypt.
- 2
Apply ROT13
The text is immediately transformed using ROT13, shifting each letter by 13 positions.
- 3
Try other shifts
Adjust the shift value to use any Caesar cipher offset from 1 to 25.
- ROT13 is its own inverse, so applying it twice returns the original text.
- Use Caesar cipher shifts other than 13 to explore basic classical cryptography concepts.
- ROT13 only affects letters; numbers, spaces, and punctuation remain unchanged.
- This is an encoding, not secure encryption. Never use it to protect sensitive data.
- Instant ROT13 encoding and decoding
- Adjustable Caesar cipher shift from 1 to 25
- Preserves case, numbers, and special characters
- Real-time output as you type
- Hide spoilers or puzzle answers in forums and messages
- Teach students the fundamentals of substitution ciphers
- Obfuscate text in casual contexts where simple concealment is enough
- Decode ROT13-encoded content found online or in puzzle games
No. ROT13 is a trivial substitution cipher that offers no real security. It is useful only for casual obfuscation, like hiding spoilers.
The English alphabet has 26 letters. A shift of 13 means encoding and decoding use the same operation, since 13 + 13 = 26.