ROT13 & Caesar Cipher Encoder / Decoder
Encode or decode text with ROT13 or a Caesar cipher of any shift (-25 to +25). Round-trip verified. Runs in your browser.
Runs 100% in your browser — nothing is uploaded.
Output (ROT13)
✓ Round-trip verified
Frequently asked
Is ROT13 encryption?
No — it's a trivially reversible cipher used only for casual obfuscation (hiding spoilers, punchlines, etc.). Never use it to hide anything real.
How is ROT13 special?
Applying it twice returns the original text. That's because 13 + 13 = 26 (one full alphabet cycle). Other Caesar shifts don't have this property.
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