🔁 ROT13 Encoder / Decoder
ROT13 rotates each letter halfway round the alphabet — the same click both hides and reveals, because doing it twice returns the original.
Transformed in your browser — nothing you type is uploaded.
How the rot13 encoder / decoder works
ROT13 ("rotate by 13") replaces each letter with the one 13 places along the alphabet: A↔N, B↔O, and so on. Because 13 is exactly half of 26, applying it a second time restores the original text — so a single operation both encodes and decodes. Non-letters are left untouched.
ROT13 provides no security whatsoever; its purpose is to lightly obscure text that a reader shouldn't see by accident — spoilers, puzzle answers, joke punchlines, offensive words on old forums. It's a convention for "look only if you mean to", not a cipher for secrets.
Frequently asked questions
What does ROT13 do?
It shifts every letter 13 positions along the alphabet (A becomes N, N becomes A). Since the alphabet is 26 letters, this is a half-rotation, and applying it twice returns the original text.
Why is the same button used to encode and decode?
Because ROT13 is its own inverse — rotating by 13 twice is a rotation by 26, which lands back where you started. So there is only one operation.
What is ROT13 used for?
Hiding text in plain sight where secrecy doesn't matter — spoilers, puzzle solutions, punchlines. It ensures you only read the hidden text if you deliberately decode it.
Is ROT13 secure?
No — it's a fixed, keyless substitution anyone can reverse instantly. It obscures, it doesn't protect. For real protection use encryption.
Is my text uploaded?
No — ROT13 is applied in your browser.