GUIDES & EDUCATIONAL ARTICLES July 13, 2026 · 7 Min Read

Base Converter – Convert Decimal, Binary, Octal and Hexadecimal

Free online base converter to convert between binary, octal, decimal, hexadecimal, and custom bases.

Number systems form the backbone of modern computing and mathematics. While we use the decimal (base-10) system for everyday counting, computers operate using binary (base-2), and programmers frequently work with octal (base-8) and hexadecimal (base-16) for more compact representations. A base converter is a tool that translates numbers from one positional numeral system to another, making it indispensable for computer scientists, electrical engineers, and anyone working with low-level data representations.

Key Takeaway

Every number system uses a base (or radix) that determines how many unique digits are available. Decimal uses base-10, binary uses base-2, octal uses base-8, and hexadecimal uses base-16. Converting between these systems relies on understanding positional value and the powers of the base.

1. Understanding Number Bases

A positional number system assigns value to each digit based on its position relative to the decimal point. In the decimal system, each position represents a power of 10. For instance, the number 3,472 means 3 x 1000 + 4 x 100 + 7 x 10 + 2 x 1. The same principle applies to other bases, but with a different radix.

In binary (base-2), only two digits exist: 0 and 1. Each position represents a power of 2. So the binary number 1011 translates to 1 x 8 + 0 x 4 + 1 x 2 + 1 x 1 = 11 in decimal. In hexadecimal (base-16), sixteen symbols are used: the digits 0 through 9 and the letters A through F, where A represents 10, B represents 11, and so on up to F representing 15. Hexadecimal is popular in computing because a single hex digit corresponds to exactly four binary digits, making it a compact way to represent binary data.

2. Conversion Methods and Algorithms

Converting from any base to decimal involves multiplying each digit by the base raised to the power of its position index (starting from 0 on the right). Converting from decimal to another base uses repeated division: divide the number by the target base, record the remainder, and continue dividing the quotient until it reaches zero. The remainders read in reverse order give the result in the target base.

For conversions between binary, octal, and hexadecimal, a shortcut exists because these bases are all powers of 2. Each octal digit maps to exactly three binary digits, and each hex digit maps to four. This allows direct grouping without going through decimal as an intermediary. For example, to convert binary 11010111 to hex, group into 4-bit segments: 1101 = D and 0111 = 7, giving D7 in hexadecimal.

3. Practical Applications

Base conversion is not just an academic exercise. Network administrators use hexadecimal to represent IP addresses and MAC addresses in a compact form. Web developers encounter hexadecimal when specifying colors in CSS (e.g., #FF5733). Memory addresses in assembly language are almost always written in hex or octal. Binary is fundamental to understanding data storage, file formats, and digital logic circuits. The base converter tool streamlines these conversions, saving time and eliminating the errors that come with manual calculation.