ROT13

Rotate letters by 13 positions with the same operation for encoding and decoding.

Alphabet mapping

ROT13 is a Caesar shift of 13 places. It pairs the alphabet in halves: A <-> N, B <-> O, C <-> P, and so on. There is no custom key.

Type: Fixed shift cipher Key: Shift 13 Direction: Same both ways A <-> N B <-> O M <-> Z

Options

Preserve case

Keep punctuation & numbers

Remove whitespace

Group letters

ROT13 is reciprocal: applying it a second time returns the original text.

Output stats

Mode: Encode Rotation: 13 Letters processed: 0 Input chars: 0 Output chars: 0 Blocks: 0

Classic example: HELLO WORLD becomes URYYB JBEYQ. Because ROT13 is reciprocal, running URYYB JBEYQ through ROT13 returns HELLO WORLD.

Input

Output

Using This Tool: Guide & Notes Show guide

ROT13 is Caesar with a fixed shift of 13. Applying it twice returns the original text.

How to use it

Paste text into the input box.
Read the rotated output.
Paste the output back in to recover the original message.
Use Load example to check common ROT13 behaviour.

Options and settings

Preserve case keeps uppercase and lowercase styling.
Keep punctuation and numbers leaves unsupported characters unchanged.
Remove whitespace creates compact output when needed.
Group letters formats the output into fixed-size blocks.

Notes

ROT13 is casual obfuscation, not encryption.
Because the shift is fixed and public, there is no secret key to protect.

The ROT13 Cipher: Thirteen Steps to Obscurity

A thirteen-letter rotation that hides text from casual view but offers almost no real protection.

Read the article

Signal acquired

A note from the team

We build these tools because we love cryptography, encoding, and making difficult ideas easier to explore. If they've helped you, even a small coffee means the world to the project. Thank you!

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