Number Base Converter (Binary, Octal, Decimal, Hex)

What is Number Base?

A number base converter translates integers between binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16). These conversions are everyday work in low-level programming, networking, bit manipulation, color codes, and file formats. Because the tool uses JavaScript BigInt, it converts integers of any size precisely — no floating-point rounding on values beyond 2^53.

How to convert between number bases

1. 1Enter your value in whichever base you have (binary, octal, decimal, or hex).
2. 2All other bases update instantly.
3. 3Use the hex output for memory addresses, color codes, or byte values.
4. 4Copy the representation you need.

Use Cases

Code Examples

Binary:   11111111
Octal:    377
Decimal:  255
Hex:      FF

Key Concepts

Positional notation

Each digit's value is its symbol times the base raised to its position. In base 16, 'FF' = 15×16 + 15 = 255.

Common prefixes

0b for binary, 0o for octal, 0x for hex in most languages. Decimal has no prefix.

BigInt

A JavaScript type for arbitrary-precision integers, letting the tool convert huge numbers without the 2^53 float limit.

Tips & Best Practices

• ▸One hex digit maps to exactly four binary digits (a nibble) — handy for reading binary in groups.
• ▸This tool handles integers; fractional base conversion is a different, less common problem.
• ▸Watch for prefixes: '0x1F' and '1F' are the same hex value; strip 0x if the field expects raw digits.
• ▸Negative integers are supported, but two's-complement width depends on your context (8/16/32/64-bit).