Shift letters by any N positions (±26) — enc/dec with custom shift. Free, private, and runs entirely in your browser — no data leaves your device. Part of our Security / Crypto tools collection.
Tips
shift=3 is the 'classic' Caesar shift Julius Caesar used
shift=13 gives ROT13 — decryption is the same operation
Only touches letters; numbers and punctuation pass through unchanged
FAQ
How do I use the Caesar Cipher?
shift=3 is the 'classic' Caesar shift Julius Caesar used shift=13 gives ROT13 — decryption is the same operation Only touches letters; numbers and punctuation pass through unchanged
Is the Caesar Cipher free and private?
Yes — it runs in your browser, requires no signup for basic use, and your data never leaves your device. Caesar is recorded using shift=3 in Suetonius's 'Life of Julius Caesar' (AD 121). It was considered unbreakable for ~1500 years until al-Kindi invented frequency analysis.
