Caesar Cipher (incl. ROT13)
Encode or decode text with a Caesar cipher shift — including ROT13 — entirely in your browser.
Output
Caesar cipher encoder & decoder
The Caesar cipher shifts each letter a fixed number of positions in the alphabet. Use the slider to choose a shift from 1 to 25. ROT13 (shift 13) is especially common online because it’s its own inverse — encode and decode are the same operation.
Non-letter characters (spaces, punctuation, numbers) are passed through unchanged. To decode, shift by 26 minus your original shift.
FAQ
Is my data sent anywhere? No — everything runs locally in your browser.