# ROT13 > Decode and encode ROT13 instantly (the same step does both), switch to ROT5, ROT18 or ROT47, or try every rotation when it is not ROT13. - Page: https://linguaholic.com/tools/rot13/ - Type: free online tool (Converters & translators), no sign-up, runs in the browser - Publisher: Linguaholic (https://linguaholic.com/), made by Marcel Iseli - Last updated: October 3, 2026 - Open it pre-filled: https://linguaholic.com/tools/rot13/?text=Uryyb+Jbeyq - `text`: text to rotate (ROT13 encodes and decodes with the same operation) (for example `Uryyb Jbeyq`) - `variant`: rot13 (default, letters), rot5 (digits), rot18 (letters and digits) or rot47 (all printable ASCII); other values are ignored (for example `rot47`) - `open`: open a section: crack (all 25 rotations ranked), steps (the ROT13 wheel and letter pairs), frequency (letter counts) or identify (which cipher is this?) (for example `crack`) ## What is ROT13? **ROT13** (“rotate by 13 places”) replaces every letter with the letter 13 places further along the alphabet, wrapping around from Z to A. A becomes N, B becomes O, and N becomes A again. Because the alphabet has 26 letters and 13 is exactly half, doing ROT13 twice brings you back where you started. That makes it unusual among ciphers: **encoding and decoding are the same operation**, so this tool has no Encode or Decode switch. Paste ROT13 text to read it, or plain text to hide it. ROT13 is a [Caesar cipher](https://linguaholic.com/tools/caesar-cipher/) with a shift of 13. It was never meant to keep secrets. It hides text from a casual glance, so that a reader has to choose to see a spoiler, a punchline or a puzzle answer. ## How to use the ROT13 decoder and encoder 1. Type or paste your text. The result appears below as you type. 2. Choose a **variant** if you need one: ROT13 for letters (the standard), ROT5 for digits only, ROT18 for letters and digits together, or ROT47 for letters, digits and symbols. 3. Press **Copy**, or **Use as input** to run the result through again (and see that it turns straight back into your original). If a text does not decode with ROT13, it may use a different rotation. Open **Crack it: I don’t know the key** to see all 25 rotations ranked by how much they read like English; that makes it a general rotation cipher decoder. **Step by step** shows the ROT13 wheel and the letter pairs, and **Which cipher is this?** helps when you are not sure what kind of code you have. Links can open the tool filled in, for example `?text=Uryyb&variant=rot13`, and `&open=crack` opens the list of rotations. ## Frequently asked questions **What is ROT13?** ROT13 replaces every letter with the letter 13 places further along the alphabet, so A becomes N and N becomes A. It is a Caesar cipher with a shift of 13. **How do I decode ROT13?** Apply ROT13 again. Because 13 is half of 26, rotating twice brings every letter back, so paste the text into the tool and the result is the decoded message. **Why are ROT13 encoding and decoding the same?** The alphabet has 26 letters. Moving 13 places and then 13 more is a full circle of 26, which returns each letter to where it started. **What is ROT13 used for?** Hiding spoilers, punchlines, puzzle answers and hints so that readers only see them if they choose to. It is a courtesy, not a way to keep secrets. **Does ROT13 change numbers?** No. Standard ROT13 only rotates letters. ROT5 rotates digits by five places, ROT18 does both, and ROT47 also changes punctuation; all are available in the tool. **What is ROT47?** A rotation of the 94 printable ASCII characters, from ! to ~, by 47 places. Letters, digits and symbols all change, and applying it twice gives the original. **What if my text is not ROT13?** It may be another rotation, such as ROT1 or ROT3. Open Crack it in the tool to see all 25 rotations ranked by how much they read like English. **Is ROT13 secure?** No. It has no key, and anyone can reverse it in a second. Never use it for passwords or private information. **How do I do ROT13 on the command line?** On Linux or macOS, pipe the text through tr 'A-Za-z' 'N-ZA-Mn-za-m'. In Python, codecs.encode(text, 'rot13') does the same. ## Data sources The code breaker's English letter frequencies and word checks come from Linguaholic’s English dictionary, built from the open ENABLE and SCOWL word lists. Licenses and notices: https://linguaholic.com/tools/data/dict/v1/NOTICE.txt ## Related tools - [Caesar Cipher](https://linguaholic.com/tools/caesar-cipher/): Encode and decode the Caesar shift cipher with any shift from 1 to 25, or crack a message without the key: every shift is tried and ranked for you. - [Atbash Cipher](https://linguaholic.com/tools/atbash-cipher/): Encode and decode the Atbash cipher, which swaps each letter with its mirror (A↔Z, B↔Y), with the alphabet chart, step-by-step working and examples. - [Vigenère Cipher](https://linguaholic.com/tools/vigenere-cipher/): Encode and decode the Vigenère cipher with a keyword, or crack a message without the key: the tool finds the key length and the keyword for you. - [Substitution Cipher](https://linguaholic.com/tools/substitution-cipher/): Encode and decode with any cipher alphabet or keyword, or paste a cryptogram and let the solver crack it; then fix any letter yourself. - [Morse Code Translator](https://linguaholic.com/tools/morse-code-translator/): Translate text to Morse code and decode it back, hear it as adjustable-speed sound with a visual flasher, and read the full Morse alphabet, number, and punctuation chart. - [Roman Numeral Converter](https://linguaholic.com/tools/roman-numeral-converter/): Convert numbers to Roman numerals and back in one box, write big numbers with the bar on top, turn any date into Roman numerals for a tattoo, add and multiply Roman numerals, and practice with a quick quiz — plus a full chart.