ROT13 for letters plus ROT5 for digits — symmetric encode & decode. ROT18 Cipher is a free online tool from the ToolsRift Encoders & Decoders collection. It runs entirely in your browser — nothing to install, no signup, and your data never leaves your device.
Enter text and the ROT18 output updates live. Letters shift 13 places and digits shift 5; running the result back through the tool restores the original.
A combination cipher: letters use ROT13 and digits use ROT5. It obscures both text and numbers while staying its own inverse.
Plain ROT13 leaves digits unchanged. ROT18 also scrambles 0-9, which is handy when the content mixes words and numbers.
Yes — like ROT13, applying ROT18 a second time returns the original, so no key is required.