Polybius Square Cipher
Security ToolsLetters to row-column number pairs (5×5 grid)
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History
All history →Polybius Square Cipher — at a glance
Turn letters into two-digit grid coordinates, or read coordinates back as text.
How to use it — step by step
Text to encode, or number pairs (11–55) to decode.
Add your text
Paste or type your input into the box. The Sample button fills in an example.
Choose the options
Pick the mode and settings you need. Results update when you run the tool again.
Press Run
The result is made instantly inside your browser.
Copy the result
Use the Copy button, or send it to another tool.
Pro tips
Small things that make the result better.
Quick facts
Frequently Asked Questions
How does the Polybius square work?+
Letters sit in a 5×5 grid. Each letter is written as its row number followed by its column number.
Why are I and J together?+
The grid has 25 cells but the alphabet has 26 letters, so I and J share one.
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.