Text Encoder and Decoder

Encode and decode text using ROT13, Caesar cipher with adjustable shift, Atbash, and text reversal.

Text Encoder and Decoder tool

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Example

Input: Hello World, Caesar Cipher with shift 3

Result: Khoor Zruog

Each letter moves 3 places forward in the alphabet (H to K, e to h) while spaces, digits and punctuation stay the same.

One Message in Each Cipher

MethodEncoded
ROT13Zrrg zr ng 9cz
Caesar, shift 1Nffu nf bu 9qn
Caesar, shift 3Phhw ph dw 9sp
Caesar, shift 10Wood wo kd 9zw
AtbashNvvg nv zg 9kn
Reversemp9 ta em teeM

Input: "Meet me at 9pm". Digits and spaces are never changed by the ciphers.

  1. Type or paste the text you want to encode or decode.
  2. Choose a cipher tab: ROT13, Caesar Cipher, Atbash or Reverse.
  3. For the Caesar cipher, set the shift from 1 to 25 with the slider and read the Encoded and Decoded results.
  4. Watch the output update as you type or change settings.
  5. Switch tabs to compare ciphers without retyping your text.
  6. Click the copy button to copy the result.

ROT13, Caesar and Atbash Ciphers Explained

This tool encodes and decodes text with three classic ciphers, ROT13, Caesar and Atbash, plus a simple reverse. With a Caesar shift of 3, "Hello World" becomes "Khoor Zruog". Only the letters A to Z change. Digits, spaces and punctuation stay put, and capital letters stay capital.

A Caesar cipher moves every letter a fixed number of places along the alphabet, wrapping from Z back to A. Julius Caesar is said to have used a shift of 3. Pick any shift from 1 to 25 with the slider and the tool shows two results. Encoded shifts the letters forward, and Decoded shifts them back, so you can read a message whichever way it was made.

ROT13 is a Caesar cipher with a shift of 13. Since 13 is half of 26, the same step both hides and reveals text: run ROT13 twice and you are back where you started. That is why forums use it for spoilers and puzzle answers. Atbash mirrors the alphabet, so A becomes Z, B becomes Y and M becomes N. It also undoes itself, and it dates back to Hebrew texts. Reverse simply writes the text backwards.

None of these ciphers is secure. There are only 25 Caesar shifts to try, and letter patterns give the answer away even faster, as the Letter Counter shows. They are great for puzzles, escape rooms, lessons and light spoiler hiding. For a code made of sounds and dashes, try the Morse Code Translator.

Frequently Asked Questions

Try every shift. Paste the message, open the Caesar tab and move the slider from 1 to 25 while you watch the Decoded box, until real words appear. A faster way for long messages is to find the most common letter, which is often E in English, and count how far it has moved.
ROT13 is a Caesar cipher with the shift fixed at 13. A general Caesar cipher lets you pick any shift from 1 to 25. Because 13 is exactly half the alphabet, ROT13 is the only shift that decodes itself. With any other shift you must move the letters back by the same amount.
Only the 26 basic Latin letters, A to Z in capital and small form, are changed. Accented letters such as é or ñ, and letters from other alphabets such as Greek or Cyrillic, pass through as they are. Remove accents first if you want every letter shifted.

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