Caesar Cipher

Text

Shift

Operation

Result

ResultТулезх, XqlWrrov
ROT13Ьэхося, HavGbbyf
Reverse transformПривет, UniTools
Shift applied3
Letters in the text14

The cipher everyone meets at school

Shift cipher for the Latin and Cyrillic alphabets, with ROT13 shown separately and the reverse transform for checking.

The Caesar cipher shifts every letter a fixed number of places along the alphabet. Julius Caesar, according to Suetonius, used a shift of three — hence the name. By modern standards it is a puzzle rather than encryption.

Breaking it is trivial: there are only as many possibilities as letters in the alphabet, and checking them by hand takes a minute. Frequency analysis is faster still — the commonest English letter is E, and the gap gives the shift directly.

What this calculator shows

The encoded or decoded text
ROT13, the shift of thirteen that is its own inverse in Latin
The reverse transform, so the result can be checked immediately

What to keep in mind

Latin and Cyrillic alphabets are supported; case is preserved and punctuation and digits pass through untouched.
Cyrillic counts ё as its own letter, giving 33 positions.

FAQs

What is ROT13?

A Caesar cipher with a shift of 13. Since Latin has 26 letters, applying it twice returns the original. Usenet used it to hide spoilers from a casual glance.

How do I break a Caesar cipher?

Try every shift — 26 for Latin, 33 for Cyrillic. Or look at the most frequent letter: E in English, and the difference gives the shift at once.

Can it protect anything?

No. It is a teaching example and a game. Real protection needs modern algorithms, and for secrets in transit, end-to-end encryption.

Why is the Vigenère cipher stronger?

Its shift changes letter by letter according to a keyword, so simple frequency analysis fails. It stood unbroken for three centuries until Kasiski found a method.

Worked example

A shift of three

Input: Привет, UniTools shifted by 3

Output: Стлеиц, XqlWrrov

Note: Punctuation and spaces stay put, which is exactly why the cipher is so easy to break: the structure of the text survives intact.

Useful links

All tools in Text tools for word count, character count, and quick cleanup

Caesar Cipher

Result

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