Is ROT13 secure encryption?

No, it's a trivial substitution cipher meant for obscuring spoilers, not for real security.

How do I decode ROT13 text?

Apply ROT13 again — since it shifts by 13 out of 26 letters, encoding twice returns the original text.

Does it affect numbers or punctuation?

No, only A-Z and a-z letters are shifted; everything else stays unchanged.

ROT13 / Caesar Cipher

Encode or decode text with ROT13 or any Caesar shift.

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No API

Shift amount

13 = classic ROT13

Input

Shifted output

Apply the same shift again to decode

Nggnpx ng qnja!

About the ROT13 / Caesar Cipher

Shift letters by any amount to encode or decode text using the classic Caesar cipher, including the popular ROT13 preset used for spoiler text and simple obfuscation.

Examples

ROT13

Hello

Output

Uryyb

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Frequently asked questions

Version 1.0.0 · Updated 2026-08-06 · Runs entirely in your browser