BYTETOOLS

ROT13 Encoder & Decoder

Encode and decode text with ROT13 instantly, add ROT5 for digits, or combine both as ROT18. A self-inverse cipher that hides spoilers and puzzle answers.

Result

Uryyb, Jbeyq! 2024

  • Instant ROT13 with no encode/decode toggle needed
  • ROT5 option to rotate the digits 0 to 9
  • ROT18 to transform letters and numbers together
  • Self-inverse — run it twice to restore the original
  • Preserves case, punctuation and spacing
  • Private, client-side rotation

How to use the ROT13 Encoder & Decoder

  1. 1

    Type or paste your text into the box.

  2. 2

    Choose ROT13 for letters, ROT5 for digits, or ROT18 for both.

  3. 3

    Read the rotated output appear instantly below.

  4. 4

    Apply the same tool again to reverse it — the cipher is self-inverse.

  5. 5

    Copy the result to your clipboard.

About the ROT13 Encoder & Decoder

The ByteTools ROT13 Encoder applies the classic letter-rotation cipher that shifts each letter 13 places. Because 13 is half of 26, ROT13 is its own inverse: the same operation both hides and reveals text, so there is no separate decode button to worry about.

Add ROT5 to rotate digits 0 to 9 as well, or pick ROT18 to transform letters and numbers together. It is the go-to trick for masking spoilers, forum puzzle answers, email addresses and other content you want readable only on demand.

All rotation happens locally in your browser with JavaScript, so nothing you type is uploaded or stored. Copy the result with a single click whenever you are ready to share it.

Frequently asked questions

What is ROT13?

ROT13 is a simple letter-substitution cipher that replaces each letter with the one 13 positions later in the alphabet. A becomes N, B becomes O, and so on. It is widely used online to hide spoilers and puzzle answers in plain sight.

Why is ROT13 its own inverse?

The alphabet has 26 letters and ROT13 shifts by exactly half of that. Rotating a second time adds another 13, for a total of 26, which brings every letter back to where it started. So encoding and decoding are the identical operation.

What are ROT5 and ROT18?

ROT5 rotates the ten digits 0 to 9 by five places, so 0 becomes 5 and it is likewise self-inverse. ROT18 combines ROT13 for letters with ROT5 for digits, transforming both in one pass, which is handy for text that mixes words and numbers.

Is ROT13 encryption?

No. ROT13 provides no security because anyone can reverse it instantly. Its only job is to obscure text from casual view, such as hiding a spoiler until the reader chooses to decode it. Never use it to protect sensitive information.

Does ROT13 affect punctuation or spaces?

No. ROT13 only rotates the 26 letters and, if you enable ROT5, the digits. Spaces, punctuation and other symbols are left exactly as they are, so the layout and readability of your text are preserved.

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