Number Base Converter
Convert numbers between binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16). Results update as you type. Free, no signup.
What is Number Base Converter?
Number base conversion is fundamental to computer science and programming. Decimal (base 10) is the system humans use daily. Binary (base 2) is how computers store and process data at the hardware level — every number is represented as ones and zeros. Octal (base 8) groups binary digits in threes and was common in early computing. Hexadecimal (base 16) groups binary digits in fours and is widely used in programming for colour codes, memory addresses, and byte values.
Hex is particularly prevalent in software development: CSS colour codes like #3b82f6 are hex values, memory dumps display data in hex, and cryptographic hashes are expressed in hex. Understanding how to read and convert between these bases is essential when working with low-level programming, bitwise operations, network protocols, and colour manipulation in CSS and design tools.
All conversions run instantly as you type in any input field. Enter a value in any base and all other representations update simultaneously. No data is sent to a server.
How to use
Frequently asked questions
Hex is used for CSS colour codes (#ff6600), CSS custom property values, and encoding binary data as URL-safe strings. It compresses binary data to half the characters compared to binary representation.
Multiply each binary digit by 2 raised to its position power, then sum. For 1010: (1×8) + (0×4) + (1×2) + (0×1) = 10.
0–9 and A–F (or a–f). Hex digits beyond 9 use letters: A=10, B=11, C=12, D=13, E=14, F=15.
Yes. All conversions run locally in your browser. Nothing is sent to any server.