Caesar cipher encoder and decoder
Shift letters to create or solve a simple cipher puzzle.
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Shifts A–Z while preserving case, spaces and punctuation. Shift 13 is ROT13. This historical cipher is easily broken and must not be used to protect secrets. Change the input or settings to update your result. Results update as you type. Up to 1,000,000 characters.
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How to use Caesar cipher encoder and decoder
- Enter text and choose a shift from -25 to 25. Use the opposite shift to decode. A shift of 13 is ROT13 and applying it twice restores the original.
- With shift 13, Hello, World! becomes Uryyb, Jbeyq!. Punctuation and capitalization are preserved.
Useful next steps
How to use it
Enter text and choose a shift from -25 to 25. Use the opposite shift to decode. A shift of 13 is ROT13 and applying it twice restores the original.
Try a small example
With shift 13, Hello, World! becomes Uryyb, Jbeyq!. Punctuation and capitalization are preserved.
What to know
Shifts A–Z while preserving case, spaces and punctuation. Shift 13 is ROT13. This historical cipher is easily broken and must not be used to protect secrets.