ROT13 / Caesar Cipher — Free Online Tool
Apply a Caesar cipher to any text by shifting each letter N positions in the alphabet. ROT13 (shift=13) is symmetric: applying it twice returns the original text. Use the shift slider to try all 25 possible Caesar shifts. Non-ASCII characters, numbers, and symbols pass through unchanged.
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How to use ROT13 / Caesar Cipher
- Type or paste text into the input area.
- Adjust the shift slider (1–25); shift=13 is ROT13.
- Output updates live as you type.
- Click a preset to load a sample, or copy the output.
Frequently Asked Questions
What is ROT13?
A 13-shift Caesar cipher where A→N, B→O, etc. Applying it twice returns the original text because 13+13=26.
Is this secure?
No. Caesar ciphers provide zero cryptographic security and are trivially brute-forced. Use AES for real confidentiality.
How is Caesar cipher different from ROT13?
ROT13 is a specific Caesar cipher with shift=13. The Caesar family covers any shift from 1 to 25.
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