Number Base
Free online number base converter. Convert between Decimal, Hexadecimal, Binary, and Octal. Supports large integers. All processing happens locally in your browser.
How to Use Number Base
Enter a Number
Type a number in any of the four input fields — Decimal (base 10), Hex (base 16), Binary (base 2), or Octal (base 8). The tool supports large integers using BigInt.
View All Conversions
As you type, all other bases are automatically calculated and displayed. The conversion happens in real-time with no delay.
Copy Any Value
Select and copy the converted value you need. Use it in your code, configuration files, or documentation.
Common Base Conversions
| Decimal | Hex | Binary | Octal |
|---|---|---|---|
| 255 | FF | 11111111 | 377 |
| 16 | 10 | 10000 | 20 |
| 42 | 2A | 101010 | 52 |
Frequently Asked Questions
What are number bases?
A number base (or radix) determines how many unique digits a numeral system uses. Decimal (base 10) uses 0-9, Binary (base 2) uses 0-1, Octal (base 8) uses 0-7, and Hexadecimal (base 16) uses 0-9 plus A-F. Each base represents the same number differently.
When do developers use different number bases?
Binary is used for bit manipulation and low-level programming. Hex is used for color codes, memory addresses, and encoding. Octal is used in Unix file permissions. Decimal is the standard for everyday use.
How does Hex to Decimal conversion work?
Each hex digit represents a power of 16. For example, 0xFF = (15 × 16¹) + (15 × 16⁰) = 240 + 15 = 255. Our tool handles this calculation automatically for any size number.
What is the largest number I can convert?
This tool uses JavaScript BigInt, which can handle arbitrarily large integers. There is no practical limit on the size of numbers you can convert between bases.
Understanding Number Bases
Number bases are fundamental to computer science. While humans use decimal, computers operate in binary at the hardware level. Hex provides a more compact, human-readable way to represent binary data.
Common Developer Uses
- Hex — CSS colors (#FF5733), memory addresses, Unicode code points
- Binary — Bit flags, bitwise operations, network masks
- Octal — Unix file permissions (chmod 755)