Number Base Converter
Convert instantly between binary, octal, decimal, hexadecimal, and any custom base from 2 to 36. Type in any field to update all others.
Quick Reference
| DEC | BIN | HEX |
| 0 | 0 | 0 |
| 8 | 1000 | 8 |
| 15 | 1111 | F |
| 16 | 10000 | 10 |
| 255 | 11111111 | FF |
| 256 | 100000000 | 100 |
| 1024 | 10000000000 | 400 |
| 65535 | 1111111111111111 | FFFF |
| HEX | DEC | BIN |
| A | 10 | 1010 |
| B | 11 | 1011 |
| C | 12 | 1100 |
| D | 13 | 1101 |
| E | 14 | 1110 |
| F | 15 | 1111 |
How to Convert Number Bases
ToolsPix Number Base Converter lets you translate any integer between binary, octal, decimal, hexadecimal, and custom bases from 2 to 36 — instantly, entirely in your browser. No data is uploaded, no account is required, and nothing is stored on any server.
What is a number base?
A number base (or radix) defines how many unique digit symbols a positional number system uses. Decimal (base 10) uses digits 0–9 because humans have ten fingers. Binary (base 2) uses only 0 and 1 because digital circuits have two voltage states. Octal (base 8) and hexadecimal (base 16) are convenient shorthands for binary — each octal digit maps to exactly 3 bits, and each hex digit maps to exactly 4 bits.
Why convert between number bases?
- Read and write CPU registers, memory addresses, and machine code in hex or binary.
- Decode Unix file permissions expressed in octal (e.g.,
chmod 755). - Inspect HTML color codes written as six-digit hexadecimal values like
#FF5733. - Understand data encoding schemes that use base 32 or base 36 for compact IDs.
How to use this converter
Type or paste a number into any of the four standard fields — Binary, Octal, Decimal, or Hexadecimal. All other fields update instantly. For a non-standard base, enter a value between 2 and 36 in the Custom base box. The bit visualizer appears automatically when you enter a value, showing each binary digit as an individual cell. Use the Copy buttons to grab any result to the clipboard.
Custom bases and extended notation
Bases 2 through 36 are supported using digits 0–9 followed by letters A–Z. Base 32 (duotrigesimal) is widely used in encoding systems like Crockford Base32. Base 36 is the most compact base representable with standard ASCII alphanumerics. This tool uses JavaScript's native BigInt for arbitrary-precision arithmetic, so very large integers are handled without rounding errors.
Frequently Asked Questions
How do I convert binary to decimal?
Type your binary number into the Binary field above and the decimal result appears instantly. Manually, you multiply each bit by its positional power of 2 and sum the results — for example, 1010 = 1×8 + 0×4 + 1×2 + 0×1 = 10.
What does hexadecimal mean?
Hexadecimal (base 16) uses the digits 0–9 plus the letters A–F to represent values 10–15. It is compact — one hex digit represents exactly 4 binary bits, so a full byte (8 bits) is always two hex digits. This is why HTML colors like #FF5733 use hex.
What are Unix file permissions in octal?
Unix permissions are expressed as three octal digits: owner, group, and others. Each digit is the sum of read (4), write (2), and execute (1). So chmod 755 means owner=7 (rwx), group=5 (r-x), others=5 (r-x).
What is a custom base?
Any integer from 2 to 36 can be a number base. Base 36 uses all digits 0–9 and letters A–Z, producing very compact representations. Base 32 is common in encoding systems. This tool supports any custom base in that range.
Does this tool support negative numbers or decimals?
This tool handles non-negative integers. For negative numbers, two's complement representation is the standard approach in computing — that's a separate topic best handled by a dedicated bitwise calculator. Floating-point base conversion is also outside the scope of this tool.