Number Base Converter
Convert between Binary, Octal, Decimal, Hex, Base32, and Base64.
Free & unlimited
All bases
Bit visualization
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Byte 0: 42
Decimal value: 42Bits needed: 6Max unsigned 8-bit: 255Max unsigned 16-bit: 65,535
All processing happens in your browser. No data is sent to any server.
About this tool
- 1
Enter a number
Type a value in any supported base: binary (0b), octal (0o), decimal, or hexadecimal (0x).
- 2
Select the input base
Choose or auto-detect the base of your input number.
- 3
View all conversions
See the number represented in binary, octal, decimal, and hexadecimal simultaneously.
- 4
Copy any result
Click to copy the converted value in your needed base with or without the prefix.
- Hex is widely used in web development for colors (#FF5733) and memory addresses.
- Each hex digit represents exactly 4 binary digits - 0xF = 1111, 0xA = 1010.
- Octal is used in Unix file permissions: 755 = rwxr-xr-x.
- Binary is the foundation of all computing - every other base is a human-friendly way to read binary.
- Convert between binary, octal, decimal, and hexadecimal
- Auto-detect input base from prefixes (0b, 0o, 0x)
- Support for large numbers beyond 32-bit limits
- Grouped digit display (e.g., binary in groups of 4)
- Copy with or without base prefixes
- Convert hex color codes to decimal RGB values for programming.
- Translate binary data for debugging low-level code and protocols.
- Calculate Unix file permission values in octal.
- Convert between bases for computer science coursework.
Hex provides a compact representation of binary data - each hex digit maps to exactly 4 bits. A byte (8 bits) is always exactly 2 hex digits, making it easy to read memory dumps, color values, and encoded data.
0b marks binary (base 2), 0o marks octal (base 8), and 0x marks hexadecimal (base 16). These are standard prefixes in most programming languages to distinguish the base from decimal.
The tool handles positive integers. Negative numbers in binary use two's complement representation, which depends on the bit width (8-bit, 16-bit, 32-bit) and is a more advanced topic.