Base Converter (Binary/Octal/Decimal/Hex)
Free online number-base converter between binary (2), octal (8), decimal (10) and hexadecimal (16). Type a value and see all four representations at once — useful for computer-science basics, programming, networking and low-level debugging. It runs locally. DeveloperRuns locally
Use this tool
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Binary (2)
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Octal (8)
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Decimal (10)
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Hex (16)
How to use
- Enter the value and choose which base it currently uses.
- All four bases update immediately below.
- Hex accepts upper or lower case, and each result can be copied.
Frequently asked questions
Does it convert fractional numbers?
This version converts integers, covering the most common programming and exam cases; fractional base conversion can be added on request.
Why does it say invalid value?
Make sure the digits match the chosen base — binary only allows 0 and 1, while hex allows 0–9 and A–F.
Does it need internet?
No, it all runs locally in your browser.