Number Base Converter
Convert numbers between binary, octal, decimal and hexadecimal.
About Number Base Converter
Binary, octal, decimal, and hexadecimal are the daily languages of computing: binary for bitmasks and permissions, hex for colors, memory addresses, and hashes, octal for Unix file modes. This converter translates a number between all bases simultaneously — type once in any base (2, 8, 10, or 16) and read every representation instantly.
The four base buttons set how your input is interpreted: enter FF with base 16 selected, and you get 255 in decimal, 11111111 in binary, 375 in octal, and so on. Beyond the standard four, Base36 (0-9 plus A-Z) appears as well — the highest base using digits and letters, common in short IDs and URL-safe encodings.
Common conversions worth knowing: 255 = FF (one byte maximum), 1024 = 400 in hex (one kilobyte), 65535 = FFFF (16-bit maximum), 0755 octal = 493 decimal (the classic chmod rwxr-xr-x). The converter handles arbitrarily large integers that would overflow 32-bit calculators elsewhere.
Frequently Asked Questions
How do I enter a hex number?
Click the 16 button first, then type the hex digits (0-9, A-F). You can also paste 0xFF-prefixed strings — the prefix is stripped automatically.
Does it handle negative numbers or fractions?
It converts non-negative integers, which covers the overwhelming majority of base-conversion needs (addresses, permissions, colors, IDs). Fractions in non-decimal bases are rarely useful outside numeric computing courses.
What is Base36 for?
Base36 packs the most information into alphanumeric characters — used for short slugs, URL-safe identifiers, and license codes where only letters and digits are allowed.