Do I need a separate decoder?

No! Because the English alphabet has 26 letters, shifting by 13 is perfectly symmetrical. Pasting ROT13 text into the encoder will instantly decode it back to normal.

Casetivo

ROT13 Encoder/Decoder

Encode and decode text using the ROT13 cipher

Characters: 0|Words: 0

How does the ROT13 Encoder/Decoder work?

The ROT13 Cipher is a simple letter substitution cipher that replaces a letter with the 13th letter after it in the alphabet. Because there are 26 letters in the alphabet, applying ROT13 twice restores the original text.

Hiding Spoilers

ROT13 has been used on internet forums since the 1980s as a way to hide movie spoilers, puzzle solutions, and punchlines from a casual glance. It prevents accidental reading while allowing anyone who wants to know the answer to easily decode it.