ToolWren › ROT13

ROT13 Encoder & Decoder

Apply the classic ROT13 cipher, which rotates each letter 13 places through the alphabet. Because 13 is half of 26, the same operation both encodes and decodes.

100% client-side · nothing is uploaded

Loading tool…

How to use the ROT13

Type or paste your text into the Input box.
The converted result appears automatically in the output area — no button to press.
Review the output, then click Copy to copy it to your clipboard.
Edit the input at any time and the result updates live.

Privacy: this tool runs entirely in your browser. Your input is never sent to, received by, or stored on any server — there are no uploads and no tracking of what you enter.

About ROT13

What is ROT13?

ROT13 ("rotate by 13") is a simple substitution cipher that shifts every letter 13 positions: A↔N, B↔O, and so on. Non-letters are left unchanged. It's a special case of the Caesar cipher.

Why it's self-inverse

Applying ROT13 twice returns the original text, because shifting by 13 and then 13 more equals a full 26-letter rotation. So one button both encrypts and decrypts.

What it's good for

ROT13 hides spoilers, puzzle answers and punchlines from casual view. It provides no real security and should never be used to protect sensitive data.

Frequently asked questions

Is ROT13 secure?

No. It has no key and is trivially reversible. It's for obscuring text from casual reading, not for protection.

Does it affect numbers and symbols?

No. Only A–Z and a–z are rotated; digits, spaces and punctuation pass through unchanged.

What about ROT47?

ROT47 rotates a wider set of ASCII characters (including digits and symbols). This tool implements classic letter-only ROT13.