Base converter
Convert numbers between binary, octal, decimal, hex and any base, right in your browser. Nothing is uploaded.
Files are processed in your browser and never uploaded.
How to use Base converter
Add your text
Type or paste your text into the input box. Everything is handled by your own browser, so nothing is sent to a server.
Set the options
Choose Enter a number.... The options are visible from the start, not hidden until you paste something.
Read it and keep a copy
The output updates as you type, so there is nothing to submit and nothing to wait for. Copy decimal, Don puts the result on your clipboard.
What this tool does
Binary, octal, decimal and hexadecimal
Enter a number in any of the four common bases and the other three update as you type, with the input base set on the row above.
Any custom base from 2 to 36
Choose Custom and set any base from 2 to 36, using the digits 0-9 then A-Z, which covers base 32 and base 36 as well as the usual ones.
Big-integer precision
Conversion uses big integers, so a 64-bit value or longer converts exactly instead of losing digits the way a floating-point conversion would.
Live conversion
There is no convert button: every keystroke updates the other bases, and Copy decimal puts the result on your clipboard.
Works offline, no sign-up
Everything is worked out in your browser, so the numbers you type are never sent anywhere and the page works with no connection.
Frequently asked questions
Is my data uploaded anywhere?
No. The conversion runs entirely in your browser and nothing is uploaded. It works offline once the page has loaded.
Which bases are supported?
Binary, octal, decimal and hexadecimal directly, plus any custom base from 2 to 36 for both reading your input and showing an extra result.
Can it handle very large numbers?
Yes. It uses big-integer maths, so even numbers far beyond the usual limits convert exactly without rounding.
What characters can I use?
Digits 0 to 9 and letters A to Z, where A means 10 up to Z meaning 35. A leading minus sign is allowed for negative numbers. Invalid digits for the chosen base are flagged.
Does it work with decimals or fractions?
It converts whole numbers (integers). Fractional values are not supported, which keeps results exact for programming and digital uses.
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