Super Boring Tools

Search tools

Find a tool by name or what it does.

ROT13 Encoder

Apply the classic ROT13 cipher or any ROT-N shift from 1 to 25. Letters rotate, everything else stays put, and you get the encoded and decoded text at once.

Rotated live as you type. Everything runs in your browser and nothing is uploaded.

Each letter moves 13 forward: a becomes n, n becomes a. At ROT13 the encoded and decoded results are identical.

How to encode or decode ROT13 online

  1. Paste your text

    Type or paste the text you want to transform into the input box; it runs live with no button to press.

  2. Choose the shift

    Leave the shift at 13 for classic ROT13, or drag the slider to any value from 1 to 25 for a different ROT-N rotation.

  3. Read both results

    The encoded output rotates each letter forward by the shift while the decoded output rotates it back, so you can go either direction.

  4. Copy the result

    Copy the encoded or decoded text with one click; letters, spacing, punctuation, and numbers all keep their positions.

Why use this tool

Classic ROT13 and every ROT-N

Start at ROT13 by default, then dial the shift anywhere from 1 to 25 to run any Caesar-style rotation. The result updates the instant you move the slider.

Encoded and decoded at once

Every change shows both directions: the input rotated forward and the input rotated back. Encode a message or recover one without retyping it.

Letters only, everything else untouched

Only A to Z and a to z rotate. Numbers, spaces, punctuation, line breaks, emoji, and accented characters pass through in place, so structure is preserved.

Case is preserved

Uppercase stays uppercase and lowercase stays lowercase, so the shifted text reads with the same capitalization as the original.

Handles long text

Paste a whole document and it rotates every letter live, keeping line breaks and spacing exactly as they were.

Runs entirely in your browser

Everything happens on your device; nothing is uploaded.

About this tool

ROT13 replaces every letter with the one thirteen places later in the alphabet, wrapping from z back to a. Because the alphabet has twenty-six letters, applying ROT13 a second time returns the original text, which is why the same operation both scrambles and unscrambles. This tool runs that rotation live as you type and also lets you pick any shift from 1 to 25, turning it into a general ROT-N or Caesar cipher. Only the twenty-six basic Latin letters move; digits, punctuation, whitespace, line breaks, and every other character stay exactly where they are, and each letter keeps its original case.

ROT13 is lightweight obfuscation, not encryption, and it has never offered real security. Its point is to hide text in plain sight: puzzle and forum spoilers, joke punchlines, answer keys, and mildly sensitive strings that should not be readable at a glance but are trivial to reveal on demand. Because the encoded and decoded results appear together, you can drop in scrambled text to read it or type plain text to scramble it without switching modes. Everything is computed in the page, so whatever you paste never leaves your device. For other reversible text transforms, try Base64 to encode data for transport, Morse code for dots and dashes, or text to binary to see each character as ones and zeros.

Frequently asked questions

What is ROT13?
ROT13 is a simple letter substitution that shifts each letter thirteen places through the alphabet, wrapping around at the end. It is a special case of the Caesar cipher, and because thirteen is half of twenty-six, encoding and decoding are the same operation.
What is the difference between ROT13 and ROT-N?
ROT-N shifts letters by any amount instead of always thirteen. Set the shift to 13 for classic ROT13, or choose any value from 1 to 25 for a different rotation. At a shift of 13 the encoded and decoded results are identical.
Does it change numbers, punctuation, or emoji?
No. Only the letters A to Z and a to z are rotated. Digits, spaces, punctuation, line breaks, emoji, and accented characters pass through unchanged and keep their positions.
Is ROT13 secure?
No. ROT13 and other ROT-N shifts are obfuscation, not encryption, and anyone can reverse them instantly. Use it to hide spoilers or answers from casual view, never to protect passwords or private data.
Is there a limit on how much text I can convert?
There is no fixed limit. The tool rotates text live as you type, and even large pasted documents are processed on your device in a single pass.
Is my text uploaded anywhere?
No. Everything runs in your browser; nothing is sent to a server.

Related tools