Number Base Converter

Type a number in any field - Binary, Octal, Decimal, or Hex - and all other fields update instantly. 100% client-side.

Last reviewed: April 2026
Reviewed by , software engineer · last updated April 2026

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Type a number in any field above to convert between bases.

Common Value Reference Table

Decimal Binary Octal Hex Char

Quick Answer

A number base converter changes a number between bases — binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16). For example, decimal 255 is 11111111 in binary and FF in hex. Enter a value in any base above to see the equivalents. Conversion happens entirely in your browser.

How to Use the Number Base Converter

To use the Number Base Converter, simply type a number into any of the input fields for Binary, Octal, Decimal, or Hex. The tool will automatically update all other fields to reflect the equivalent values in the other bases. For example, entering the decimal number 255 will instantly update the Binary field to 11111111, the Octal field to 377, and the Hexadecimal field to FF.

When to Use the Tool in Real Workflows

The Number Base Converter is ideal for developers, programmers, and anyone who needs to work with different number bases. It's particularly useful when debugging code, working with binary data, or converting values for compatibility with different programming languages.

How It Works

The Number Base Converter operates entirely on the client side, using JavaScript to perform the conversions in real-time. No data is sent to a server, ensuring that all operations are fast and secure. The tool supports conversion between binary, octal, decimal, and hexadecimal, making it a versatile resource for developers and students alike.

Tips, Edge Cases, or Limitations

The tool is designed to handle a wide range of inputs, but it may not work correctly with very large numbers or non-numeric characters. Always ensure that the input is a valid number in the specified base. Additionally, the tool does not support conversion between other number bases (such as base 3 or base 12), as these are less commonly used in modern computing.

Frequently Asked Questions

A number base (or radix) determines how many unique digits a number system uses. Decimal (base 10) uses 10 digits (0-9), binary (base 2) uses 2 digits (0 and 1), octal (base 8) uses 8 digits (0-7), and hexadecimal (base 16) uses 16 symbols (0-9 and A-F). All these systems represent the same numbers in different notations.
Computers use binary because electronic circuits naturally have two states: on (1) and off (0). Representing data with just two states is simple, reliable, and immune to small variations in voltage. Every piece of data a computer processes is ultimately stored and transmitted as binary.
Hexadecimal is used in programming because it provides a compact and human-readable way to represent binary data. Each hexadecimal digit corresponds to exactly 4 binary digits, making it easy to convert between binary and hexadecimal. This is particularly useful for representing memory addresses, color codes, and other binary data in a more manageable format.
To convert a decimal number to binary, you can use the division-by-2 method. Divide the decimal number by 2, write down the remainder, and continue dividing the quotient by 2 until the quotient is 0. The binary number is the sequence of remainders read from bottom to top.
The 0b, 0o, and 0x prefixes are used to denote binary, octal, and hexadecimal literals in programming languages, respectively. For example, 0b1111 represents the binary number 1111, 0o755 represents the octal number 755, and 0xFF represents the hexadecimal number FF.

Example walk-through

Worked example: step by step

Step 1. Navigate to the Number Base Converter webpage and locate the input field. Enter the decimal number 42 and select "Decimal" as the source base.

Step 2. Choose "Hexadecimal" as the target base from the dropdown menu. Click the "Convert" button to initiate the transformation process.

Step 3. The tool will process the input by dividing the decimal value by 16 and recording remainders. This produces the hexadecimal equivalent 2A.

Step 4. The webpage displays the result in a formatted box, showing the conversion 4210 = 2A16 with a brief explanation of the mathematical steps.

Input: 42 (Base 10)
Output: 2A (Base 16)  // 42 ÷ 16 = 2 (remainder 10)