Caesar Cipher
Encrypt and decrypt text with a configurable shift
Caesar Cipher is a free online tool from BrowserUtils that encrypt and decrypt text with a configurable shift. It runs entirely in your browser — your data never leaves your device. No account required.
How to use Caesar Cipher
- 1 Paste or type your input into the editor above.
- 2 The tool processes your data instantly — right in your browser, with nothing sent to a server.
- 3 Copy the result with one click or continue editing your input.
About Caesar Cipher
Free online Caesar cipher tool. Encrypt or decrypt text by shifting letters through the alphabet with a configurable offset. This tool runs entirely in your browser — your data is never sent to a server. Just paste your input, get instant results, and copy with one click. No sign-up or installation required.
Caesar Cipher specs
- Runtime
- 100% client-side (browser)
- Built on
- TextEncoder, TextDecoder, btoa/atob, and encodeURIComponent — all Web Platform APIs
- Cost
- Free — no account, no rate limits, no usage caps
- Browser support
- Chrome 90+, Firefox 88+, Safari 14+, Edge 90+
- Part of
- 299 developer tools on BrowserUtils (100% client-side)
Questions
What is the Caesar cipher?
The Caesar cipher is one of the oldest encryption techniques. It shifts each letter in the text by a fixed number of positions in the alphabet. ROT13 is a special case with a shift of 13.
Is the Caesar cipher secure?
No. With only 25 possible shifts it can be broken trivially by trying all possibilities (brute force). It is useful for learning about ciphers but not for real security.
How do I crack a Caesar cipher?
Try all 25 possible shifts and look for readable text, or use frequency analysis to match the most common letters in the ciphertext to common English letters like E, T, and A.
Does the Caesar cipher work with non-English alphabets?
This tool shifts the 26 English letters (A-Z). Other characters like numbers, spaces, and punctuation are left unchanged.
Can I use the Caesar cipher for a geocaching puzzle?
Yes, Caesar ciphers are commonly used in geocaching and puzzle games. Paste the encoded text and try different shift values until the message becomes readable.
How do I decrypt a Caesar cipher without knowing the shift?
Try all 25 possible shifts (brute force) and look for the output that produces readable text. The tool makes this easy by letting you cycle through shifts quickly.
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