Number Base Converter Online Free
Convert numbers between binary, octal, decimal, and hexadecimal instantly. Free, no signup required.
How to Convert Number Bases Online
- 1
Select the input base
Choose whether your number is in binary, octal, decimal, or hexadecimal by clicking the corresponding input tab.
- 2
Type your number
Enter the number in the input field. Valid characters are shown for each base (e.g. only 0 and 1 for binary). The other three bases update instantly.
- 3
Copy the result
Click Copy next to any output field to copy that representation to your clipboard.
Number base conversion is a fundamental skill in computer science, electronics, and low-level programming. Different number systems are used in different contexts: binary for CPU logic, hexadecimal for memory addresses and colour codes, octal for Unix file permissions, and decimal for everyday human-readable numbers.
How the conversion works:Any number in any base is first converted to its decimal (base-10) integer value using the positional value of each digit, then re-expressed in the target base. This tool uses JavaScript's parseInt(str, radix) and Number.prototype.toString(radix) built-in methods, which handle all four bases natively.
Hex and binary relationship: Each hexadecimal digit maps exactly to 4 binary bits. This makes hex a human-friendly shorthand for binary data: 0xFF = 11111111₂, 0x0A = 00001010₂. Programmers frequently switch between these two when inspecting raw byte values.