IconVault's ROT13 Cipher tool encodes and decodes ROT13 text instantly, and also works as a full Caesar cipher tool with an adjustable shift from 1 to 25. Type or paste your text and the output updates live as you type; flip between Encode and Decode with one tap. Non-letters pass through untouched, and letter case is preserved.

Everything runs 100% in your browser, so nothing you encode ever leaves your device, and copying the result is all it takes to use it. It is free with no signup. The honest note: ROT13 and Caesar shifts are puzzles and obfuscation, not real encryption. They are great for spoilers, geocaching hints and classroom demos, but anything that must stay secret needs real encryption like AES.