Binary / Hex / Decimal
Convert between binary, hexadecimal and decimal number bases
About this tool
This free number base converter converts between the four most common numeral systems: decimal (base 10), binary (base 2), hexadecimal (base 16), and octal (base 8). Edit any field and the other three update instantly. It is an essential tool for programmers, computer science students, and anyone working with low-level code, color values, or networking.
Each base explained: Decimal is the everyday system (digits 0–9). Binary is the language of computers — every file, image, and program is ultimately stored as a sequence of 0s and 1s. Hexadecimal uses digits 0–9 and letters A–F (where A=10, B=11, ... F=15) and is heavily used in programming because one hex digit represents exactly four binary digits (a nibble), making binary data compact and readable. Octal (base 8) uses digits 0–7 and appears in Unix file permission modes (e.g. chmod 755).
Common conversions: the decimal number 255 is 0xFF in hex (the maximum value of a single byte, seen in HTML/CSS colors like #FFFFFF for white). The number 10 in binary is 2 in decimal. Web colors are written in hex — #FF5733 means red=255, green=87, blue=51 in decimal. Understanding these conversions is fundamental to web development, networking (IP subnet masks), and embedded systems programming.
To convert from binary to decimal manually: write out each bit position as a power of 2 (2⁰=1, 2¹=2, 2²=4, ...) and add together the positions where the bit is 1. For hex, remember A–F represent 10–15. This converter does all that instantly for any value you enter.