---
title: "ROT13, Caesar and Morse — free, runs in your browser"
description: "Encode and decode ROT13, Caesar shifts, Morse code and Atbash. Free, no sign-up, and nothing you enter leaves your browser."
url: https://atoneplace.net/tools/cipher-tool/
site: "At One Place"
---

# ROT13, Caesar and Morse

Encode and decode ROT13, Caesar shifts, Morse code and Atbash.

## How it works

Converts text through the classical ciphers: ROT13, any Caesar shift, Atbash and Morse code.

None of these provide any security whatsoever, and that is worth stating plainly. A Caesar cipher has 25 possible keys and can be broken by trying all of them; ROT13 is a Caesar shift of 13 and is not even trying, being its own inverse and used only to hide spoilers from casual reading. Atbash reverses the alphabet and has no key at all.

Morse is not a cipher but an encoding, designed for transmission over a channel that can only be on or off. Its letter assignments are frequency-weighted — E is a single dot and T a single dash, because they are the two commonest letters in English, which is the same principle modern compression uses.

> This tool runs entirely in your browser. Nothing you enter is sent to a server, logged or stored, and the page keeps working with the network disconnected.

## Common questions

### Is ROT13 secure?

Not remotely. It is a fixed shift with no key, used to hide spoilers from accidental reading rather than to protect anything.

### Why is E a single dot in Morse?

The code is frequency-weighted. The commonest letters got the shortest symbols, which is the same idea behind modern compression.

## Related pages

- [Word and character counter](https://atoneplace.net/tools/word-counter/)
- [Typing speed test](https://atoneplace.net/tools/typing-speed-test/)
- [Remove duplicate lines](https://atoneplace.net/tools/remove-duplicate-lines/)
- [Sort lines alphabetically](https://atoneplace.net/tools/sort-lines/)
- [JSON formatter and validator](https://atoneplace.net/tools/json-formatter/)
- [Text compare](https://atoneplace.net/tools/text-diff/)
- [Regex tester](https://atoneplace.net/tools/regex-tester/)
- [Case converter](https://atoneplace.net/tools/case-converter/)
- [Remove empty lines](https://atoneplace.net/tools/remove-empty-lines/)
- [Find and replace](https://atoneplace.net/tools/find-and-replace/)

## Sources

- Calculated on this page — At One Place (/about/)