SummaryLog

Number Base Converter

Convert numbers between binary, octal, decimal, and hexadecimal. Supports arbitrarily large numbers via BigInt.

Enter a number above to see conversions in all bases.

Quick Examples

This number base converter turns a single value into its binary, octal, decimal, and hexadecimal forms all at once. Type a number, pick its base, and every other representation appears instantly side by side, each with its own copy button. It accepts the usual programmer prefixes (0x, 0b, 0o) and digits are grouped for readability.

It is handy when you are debugging memory dumps, reading register values, working with bitmasks, or checking a color or permission code. Because it uses BigInt, it converts arbitrarily large integers without losing precision, so 64-bit and larger values stay exact instead of rounding like normal floating-point math would.

How to use

  1. Type or paste your number into the input field.
  2. Select the base of what you entered: Binary (2), Octal (8), Decimal (10), or Hexadecimal (16).
  3. Read the converted values for all four bases in the results list below.
  4. Click Copy next to any result to put that representation on your clipboard.
  5. Use the Quick Examples buttons, like 255 or DEADBEEF, to load sample values fast.

FAQ

What is the largest number I can convert?
There is no fixed limit. The converter uses JavaScript BigInt, so it handles integers far beyond 64 bits exactly, with no rounding or loss of precision.
Do I need to add the 0x or 0b prefix?
No. The prefix is optional. If you paste a value like 0xFF or 0b1010 it strips the prefix automatically, but FF or 1010 with the matching base selected works just as well.
Does it support negative numbers?
Yes. Prefix the value with a minus sign, such as -255. The sign is preserved across all four base representations.
Why are the digits shown in spaced groups?
Output is grouped for readability: binary and hexadecimal in groups of four, octal and decimal in groups of three. The Copy button always copies the clean value without the spaces.
Is my input sent to a server?
No. All conversion runs locally in your browser. Nothing you type is uploaded, so it is safe for sensitive values.