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Number System Converter — Binary, Octal, Decimal, Hex Free Online

Convert Between Number Bases Instantly

Number System Converter converts values between binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16) as you type — plus any custom base from 2 to 36.

Features

  • Live conversion — type in any field and all others update instantly
  • Negative numbers — full support with - prefix
  • Grouped binary — bits split into 4-bit nibbles for readability
  • Number properties — bit length, byte length, is prime, is even, is power of 2
  • Custom base — convert to any base between 2 and 36
  • ASCII lookup — shows the character, Unicode code point, and whether it is printable
  • One-click copy for each field

Try It

👉 number-system-converter.pages.dev

Type 255 in the decimal field and instantly see 11111111 (binary), 377 (octal), and FF (hex). Change the custom base to 36 to see 73.

Tech

Pure Vanilla JS with zero dependencies. All conversions use JavaScript's built-in parseInt(str, base) and Number.toString(base). Runs entirely in the browser on Cloudflare Pages.


Part of devnestio — free browser tools for developers.

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