Number Base Converter: Convert Between Binary, Octal, Decimal, and Hex
Enter a number in any base and see it instantly converted to binary, octal, decimal, and hexadecimal. Essential for developers working with low-level data, colors, or permissions.
Introduction
If you have ever stared at a hexadecimal color code like #FF6B35 and wondered what the decimal values are, or tried to decipher Unix file permissions like 0755 in binary, this tool is for you. Our Number Base Converter lets you type a value in any base (binary, octal, decimal, or hexadecimal) and see the equivalent in all other bases instantly. It handles integers of any size and updates all outputs as you type. No formulas to remember, no calculator needed.
Step-by-Step Guide
Select your input base
Choose which number system you are starting from: binary (base 2), octal (base 8), decimal (base 10), or hexadecimal (base 16). The input field validates your entry for that base.
Enter your number
Type the number in the selected base. For hex, use A through F for digits 10 through 15. For binary, only 0 and 1 are valid. The tool flags invalid characters immediately.
Read the converted values
The results panel shows your number expressed in all four bases simultaneously. Click any output to copy it. Changes update in real time as you edit the input.
Pro Tips & Best Practices
When working with CSS colors, remember that each hex color is three pairs of hexadecimal digits: #RRGGBB. Use this tool to convert each pair to decimal (0 to 255) for RGB notation.
For Unix permissions, octal is the native format. 755 in octal means rwxr-xr-x. If you want to understand the binary breakdown (111 101 101), paste the octal value here.
Programmers debugging memory addresses or bitwise operations will find the binary output particularly useful. Seeing the individual bits makes bit mask operations much clearer.
Common Mistakes to Avoid
Frequently Asked Questions
Why do computers use binary?
Computer hardware is built from transistors that have two states: on and off. Binary (base 2) maps directly to these physical states. Higher bases like hex are human convenience layers that represent groups of binary digits.
When is octal actually useful?
Octal is most commonly used in Unix/Linux file permissions (like chmod 644). Each octal digit represents exactly 3 binary bits, which maps perfectly to read, write, and execute flags.
What is the largest number I can convert?
The tool supports numbers up to the limits of JavaScript safe integers (2^53 - 1 or about 9 quadrillion). For cryptographic or arbitrary-precision needs, use a dedicated math library.