ROT13 & Caesar Cipher
ROT13 and Caesar cipher with an adjustable shift
What is ROT13 & Caesar Cipher?
This ROT13 and Caesar cipher tool substitutes each letter with the one a fixed number of positions away, with the shift adjustable from 1 to 25 while digits and punctuation pass through untouched. ROT13 (a shift of 13) is its own inverse, which is why it is used to hide spoilers rather than to encrypt anything. Everything runs locally.
How to use ROT13 & Caesar Cipher
- 1Set the shift amount, or click "ROT13" to snap back to 13.
- 2Enter your text and the result is generated instantly.
- 3To reverse a shift, set the amount to 26 minus the original — or just run ROT13 a second time.
Frequently asked questions
Is ROT13 actually encryption?+
No. It is a fixed substitution with no key, so anyone who sees the output can reverse it immediately, often by eye. Its real purpose is to keep text from being read at a glance — hiding an answer or a spoiler. Anything that genuinely needs to stay secret requires real encryption.
Why is the Caesar cipher so easy to break?+
The key space holds only 25 possibilities, so trying them all takes no effort. Even without brute force, English letter frequencies reveal the shift directly. It is the earliest illustration of why modern cryptography insists the key space must be large.
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