Convert numbers between binary, octal, decimal, and hexadecimal bases in real time. Free online number base converter with instant results as you type.
Number Base Converter is a free online tool that converts numbers between the four most commonly used numeral systems: Binary (base 2), Octal (base 8), Decimal (base 10), and Hexadecimal (base 16). Simply select the input base, type your number, and see all four representations update in real time. This tool handles integer conversions accurately and is processed entirely in your browser, making it fast and private. It is an essential utility for programmers, electrical engineers, and computer science students who frequently work with different number systems.
Use the Number Base Converter when you need to quickly translate between bases during programming, hardware debugging, or studying computer architecture. It is handy when reading memory addresses in hex, working with bitwise operations in binary, interpreting Unix file permissions in octal, or calculating color values in hexadecimal. The real-time conversion removes the need to manually compute each base, saving time and reducing calculation errors during development tasks.
Software developers and students frequently use Number Base Converter to convert memory addresses and pointers from hex to decimal for debugging, translate bit masks and flags between binary and hex, interpret file permission values in octal format, convert color codes between hex and decimal representations, analyze network protocol data expressed in hexadecimal, and verify manual base conversion homework or exam problems. It is particularly valuable in embedded systems programming, systems-level debugging, and computer networking.
Essential terms and definitions related to Number Base Converter.
A number system using only two digits: 0 and 1. Binary is the fundamental language of computers — every piece of data is ultimately stored and processed as binary values. Each binary digit (bit) represents an on/off state in an electronic circuit. Eight bits make one byte, which can represent 256 different values (0-255).
A number system using 16 symbols: 0-9 and A-F. Hexadecimal is widely used in programming because each hex digit maps exactly to 4 binary bits, making it a compact and human-readable representation of binary data. Common uses include memory addresses, color codes (#FF5733), and byte values in debugging.
A number system using digits 0-7. Octal was historically important in early computing (PDP-8, Unix file permissions). Today its primary use is Unix/Linux file permissions: chmod 755 sets rwxr-xr-x, where each digit represents a 3-bit permission group (read=4, write=2, execute=1).
The tool uses JavaScript BigInt for conversions, which supports arbitrarily large integers. You can convert numbers with hundreds of digits without losing precision, unlike tools limited to 64-bit integers.
The tool focuses on the four most commonly used bases in programming: binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16). Custom bases like base 3 or base 36 are not currently supported.
The tool is designed for unsigned (positive) integers. For negative numbers in binary representation (such as two's complement), you would need to handle the sign bit manually.
No. This tool converts whole integers only. Floating-point base conversion involves additional complexity with repeating fractions and is not supported in this tool.
Common errors developers encounter and how to resolve them.
Invalid character error: Character "G" or higher in hexadecimal input Hexadecimal (base 16) only accepts the characters 0-9 and A-F. Entering an invalid character like "G" causes parseInt() to return NaN. Verify that your input contains only characters valid for the target base: binary uses 0-1, octal uses 0-7, decimal uses 0-9, and hexadecimal uses 0-9 and A-F.
Precision loss: Last digits become zero for large numbers In JavaScript, numbers above Number.MAX_SAFE_INTEGER (2^53 - 1 = 9007199254740991) suffer from precision loss due to IEEE 754 floating-point arithmetic. This tool uses BigInt to solve this problem, but when working with large numbers in your own code, use the BigInt type or arbitrary-precision libraries.
Octal prefix confusion: 0o vs 0 prefix difference In ES6+ JavaScript, octal numbers are written with the 0o prefix (e.g., 0o17). The legacy 0 prefix syntax (017) produces a SyntaxError in strict mode. When entering octal values in this tool, enter the number directly without any prefix and select Octal as the input base.