Caesar Cipher & ROT13
Text ToolsEncode and decode text with a letter shift
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All history →Caesar Cipher & ROT13 — at a glance
Encrypt or decrypt text with the classic Caesar cipher by shifting letters by any number.
ABC (shift 3)
Run
DEF
How to use it — step by step
A message in English letters.
1
Paste your input
Paste or type your content into the big input box. Try a sample if you want to see it work.
2
Choose options
Pick the mode and options that fit what you need.
3
Run cipher
Press the button. The result is created instantly on your device.
4
Copy the result
Check the output and press Copy to use it anywhere.
Pro tips
Small things that make the result better.
✦Decode with the same shift number you used to encode.
✦ROT13 is its own reverse — encode twice and you get the original.
✦Only A–Z letters change; numbers and symbols stay.
Quick facts
Freeno signup, no limit
Instantresult in a moment
Privatenothing is uploaded
Any devicephone, tablet or PC
Frequently Asked Questions
Is the Caesar cipher secure?+
No. It only has 25 possible keys and is easy to crack. Use it for fun and learning, never for real secrets.
Is my data safe?+
Yes. Everything runs inside your own browser. Your text, files and images are never uploaded to any server.
Is this tool really free?+
Yes — completely free, no signup, no watermark and no usage limit.
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