Number System Converter Free - Binary Hex Octal Online

About this tool

Binary, decimal, hex, and octal appear constantly in computer science - from memory addresses and color codes to bitmasking and register values. Converting mentally between them is error-prone; a calculator gives you the correct value immediately.

Convert instantly between binary (base 2), decimal (base 10), hexadecimal (base 16), and octal (base 8). Enter a value in any base and see the equivalent in all four formats simultaneously.

How to use Number System Converter

1. Step 1: Enter a Number. Type a number in binary, decimal, octal, or hexadecimal.
2. Step 2: Auto Convert. All other formats update instantly as you type.
3. Step 3: Copy Any Format. Click copy next to binary, decimal, octal, or hex to grab the value.
4. Step 4: Try Another. Clear and enter a new number in any base to convert again.

Where this tool helps

Convert binary to decimal for CS coursework and assignments, convert hex color codes to decimal RGB values, convert decimal to binary for bitmasking and flag operations, convert octal to binary for Unix file permissions, debug memory addresses shown in hexadecimal, and practice number system conversions for CS exams.

• Converts between all four number systems simultaneously - change one, all others update instantly.
• Supports hexadecimal input with A–F notation; no manual case conversion needed.
• Useful for CS coursework, embedded systems programming, and low-level debugging.

The most common question is how to convert binary to decimal manually - and why computers use binary in the first place. The short answer: transistors have two states (on/off), which maps directly to 1 and 0. Everything a computer does reduces to binary at the hardware level.