How to apply ROT13 substitution to text

1. Paste the text

   Drop the plaintext into the "Text" field. ROT13 shifts each A–Z letter by 13 positions (`A↔N`, `B↔O`, …, `M↔Z`). Case is preserved; digits, punctuation, spaces, and non-Latin characters are left untouched.

2. Press Run

   Result returns a single `encoded` field. Examples: `Hello, World!` → `Uryyb, Jbeyq!`; `5 PM` → `5 CZ`. Apply ROT13 twice and you get the original back — encoder and decoder are identical operations.

3. What it isn't

   ROT13 is a curiosity, NOT encryption. It hides text from a casual reader (joke punchlines, mild spoilers) but anyone can reverse it in seconds. Don't use it for passwords, secrets, or anything that needs to stay confidential.

4. When to use it

   Forum spoiler tags, puzzle hints, Easter eggs, USENET tradition. If you want to obfuscate code constants from grep, ROT13 buys you about 3 seconds — pick anything else.