Number Base Converter
Convert numbers between Binary, Octal, Decimal, and Hexadecimal. Arbitrary precision via BigInt.
Edit any field — the rest update live. Arbitrary-precision (BigInt), so numbers of any size work.
About Number Base Converter
Instantly convert numbers between binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16). Uses JavaScript BigInt for arbitrary-precision integers — no overflow for large numbers. Updates all four representations live as you type in any field. Useful for low-level programming, bitwise operations, memory address calculations, and color value conversions.
All processing happens entirely in your browser using modern web APIs. Nothing is uploaded to our servers — your data stays local and private. Free to use forever.
Common use cases
- Converting decimal values to hexadecimal for CSS color codes or memory addresses
- Understanding binary representations of integers for bitwise operations
- Converting between bases when working with low-level or embedded systems code
- Learning number bases for computer science coursework
- Reading hex values from debugging tools and converting to decimal
How it works
Each input field uses BigInt() to parse the value in its respective base (binary: parseInt(n, 2), octal: parseInt(n, 8), decimal: BigInt(n), hex: parseInt(n, 16)). BigInt is used instead of Number to handle integers larger than Number.MAX_SAFE_INTEGER (2^53 - 1) without precision loss. Conversion uses toString(base) on the BigInt value.