Convert numbers between Binary, Octal, Decimal and Hexadecimal instantly.
The Number Base Converter instantly translates any integer between binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16) - all four fields update simultaneously as you type. It is an invaluable tool for programmers, computer science students, and electrical engineers who regularly switch between number systems when reading memory addresses, color codes, or bitfield values. All conversion happens in-browser with zero latency.
The converter uses JavaScript's parseInt(value, sourceBase) to parse the input string in the given base into a standard decimal integer, then calls number.toString(targetBase) to render that integer in each of the four target bases simultaneously. This approach is accurate for non-negative integers up to JavaScript's safe integer limit of 2^53 - 1 (9,007,199,254,740,991 in decimal), which covers the vast majority of practical values encountered in programming, debugging, and computer science coursework.
The tool handles integers accurately up to JavaScript's Number.MAX_SAFE_INTEGER, which is 2^53 - 1 (approximately 9 quadrillion in decimal, or 1FFFFFFFFFFFFF in hex). Beyond this limit, JavaScript's 64-bit floating-point representation loses integer precision and conversions will produce incorrect results. If you need to convert very large integers - such as 64-bit register values or 256-bit cryptographic hashes - you would need a BigInt-capable tool or a programming language with arbitrary-precision arithmetic.
This tool is designed for non-negative integers only, which covers the most common developer needs such as memory addresses, colour codes, bitmasks, and port numbers. Negative integers and fractional (floating-point) values are not supported - entering a decimal point or a minus sign will trigger an invalid input error. For signed integer representations (two's complement) or binary fractions, you would need a more specialised tool or a calculator with explicit two's complement mode.
Different number bases are used in different contexts: binary (base 2) is the native language of CPUs and is used for bitmasks, permission flags, and digital circuit design; hexadecimal (base 16) is a compact representation of binary data used for memory addresses, colour codes (#FF5733), and machine code; octal (base 8) appears in Unix file permissions (chmod 755) and some legacy protocols; and decimal is the base humans naturally use for arithmetic and counting. Switching between these bases is a daily task for systems programmers, embedded engineers, and computer science students.
Windows Programmer Calculator and macOS Calculator in programmer mode both support base conversion and bitwise operations, but require switching between apps and do not update all four bases simultaneously as you type. This browser tool fills all four fields in real time from whichever field you edit, making it faster for rapid back-and-forth comparisons. It also requires no installation and is accessible on any device - useful when working on remote machines, tablets, or locked-down corporate workstations where installing apps is restricted.