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Number Base Converter

Math

Convert between binary, octal, hex, and decimal

Enter a number in binary, octal, decimal, or hexadecimal and see it converted to all the others simultaneously, useful for turning a hex color or a bitmask into decimal, or checking a binary string from a datasheet against its hex equivalent. Conversion uses arbitrary-precision integer math rather than JavaScript's regular number type, so it isn't limited to values that fit safely in a standard 64-bit float and can handle numbers far larger than typical calculators allow. Negative values are only supported when entering decimal directly; binary, octal, and hex input are treated as unsigned, so a leading minus sign on those bases isn't recognized. Prefixes like `0x` or `0b` and stray whitespace or underscores in the input are stripped automatically before conversion.

binaryhexoctalconvert

How to use Number Base Converter

  • 1.Enter a decimal number to instantly see its binary, octal, and hexadecimal equivalents side by side.
  • 2.Paste a hex color or bitmask value from code to convert it back to decimal for easier mental math.
  • 3.Convert a binary string from a networking or embedded systems context into hex to compare against a datasheet.

Frequently asked questions

What's the largest number this supports?
There's no practical ceiling — conversions use JavaScript's BigInt under the hood rather than native numbers, so it isn't limited to the 2^53 - 1 safe integer range and can handle arbitrarily large values, limited only by your browser's memory and how long you're willing to wait for very large numbers to render.
Does it handle negative numbers?
Support varies by representation — check how negative values are displayed (two's complement vs. a leading minus sign) since conventions differ across binary/hex contexts.
Is my input sent anywhere?
No, all conversion happens locally in your browser.
Can I convert directly between two non-decimal bases, like binary to hex?
Yes, you can enter a value in any supported base and see it converted to all the others simultaneously, not just to and from decimal.

Use via API, SDK, or MCP

cURL# Free: 1,000 req/day · Pro: 10,000 req/day
curl -X POST https://api.utilix.tech/v1/tools/number-base \
  -H "Authorization: Bearer utx_live_..." \
  -H "Content-Type: application/json" \
  -d '{"input":"255","from":10,"to":16}'

Get an API key from your dashboard · Full API docs →

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