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Number Base Converter

Convert numbers between binary, octal, decimal, hexadecimal, and any base 2–36. Big-integer safe.

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About the Number Base Converter

Convert numbers between binary, octal, decimal, hexadecimal, and any base from 2 to 36 — accurately, even for very large values.

What this tool does

Enter a number in any base and instantly see it in binary, octal, decimal, and hexadecimal, plus a custom base of your choice. It uses big-integer math so results stay exact for numbers far beyond the usual 64-bit limit.

Why it matters

Base conversion is everyday work in programming and networking:

  • Hex for colors, memory addresses, and byte values.
  • Binary for bitmasks, flags, and permissions.
  • Octal for Unix file permissions (chmod).
  • Custom bases for encoding schemes and puzzles.

Tips

You can enter negative numbers, and hexadecimal input is case-insensitive. Change the input base to interpret the same digits differently.

FAQ

How large a number can it handle?
Effectively unlimited. It uses JavaScript BigInt, so there is no 32-bit or 64-bit overflow.
Does it support negative numbers?
Yes. Prefix the value with a minus sign and every output base will reflect it.
What is a custom base?
Any radix from 2 to 36, using digits 0-9 then A-Z. Base 16 is hex; base 36 uses the full alphabet.
Is my input uploaded?
No. All conversion runs locally in your browser.

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