#FF
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Convert colors between HEX, RGB, HSL, and CMYK — online color converter with live preview.
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Hex / Binary / Decimal Converter
Convert numbers between binary, octal, decimal, and hex - instantly, any size.
number-base-converter.tool
Input is in:
Binary (0b)
11111111
Octal (0o)
377
Decimal
255
Hex (0x)
FF
Uses arbitrary-precision math, so very large numbers convert accurately - everything runs locally in your browser.
What is a hex / binary / decimal converter?
This tool converts numbers between binary, octal, decimal, and hexadecimal simultaneously - type a number in any base and see it instantly represented in the other three. It uses arbitrary-precision arithmetic internally, so very large numbers convert accurately instead of losing precision.
How to use this tool
- 1Select which base your number is currently in (Binary, Octal, Decimal, or Hex).
- 2Type the number - all four representations update instantly.
- 3Copy any of the four results individually.
Common use cases
Converting a hex color or memory address to decimal for a calculation
Working out binary representations while learning or teaching computer science
Converting file permission octal values (like 755) to other bases
Quickly checking a hex value from a debugger or log against its decimal equivalent
Good to know
Frequently asked questions
Does it handle very large numbers correctly?
Yes - it uses JavaScript's BigInt internally rather than regular numbers, so values far beyond Number.MAX_SAFE_INTEGER still convert without losing precision.
Can I paste a number with a 0x or 0b prefix?
Yes - common prefixes like 0x, 0b, and 0o are automatically stripped before parsing, so you can paste values directly from code.
What happens if I enter invalid digits for the selected base?
You'll see a clear error - for example, entering "2" while Binary is selected is flagged immediately, since binary only allows 0 and 1.
Is my input sent anywhere?
No - all conversion happens locally in your browser.
quick_facts.json
{
"runs_in_browser": true,
"data_sent_to_server": false,
"signup_required": false,
"price": "free",
"category": "Converters"
}