Number Base Converter — Binary, Decimal, Hex & Octal
Enter a number in any base and see it converted to binary, octal, decimal, hexadecimal, and custom bases instantly. Includes bitwise operations and a handy reference table.
How to use this tool
- 1Select the input base
Choose the number system of your input: Binary (2), Octal (8), Decimal (10), Hexadecimal (16), or a custom base from 2 to 36.
- 2Enter your number
Type or paste your number into the input area. All four output cards (Binary, Octal, Decimal, Hex) update simultaneously as you type.
- 3Copy the result
Click the copy button on any output card to copy the value. Toggle hex case with the Aa button. Expand bitwise operations for AND, OR, XOR, and shift operations.
Understanding number bases
Binary (Base 2)
Binary is the language of computers. Every piece of digital data is ultimately stored as sequences of 0s and 1s. Each digit (bit) represents a power of 2. Eight bits form a byte, which can represent values from 0 to 255.
Hexadecimal (Base 16)
Hex uses digits 0-9 and letters A-F. It is widely used in programming for colour codes (#FF5733), memory addresses, and byte representation. Each hex digit maps to exactly 4 binary bits, making it a compact way to display binary data.
Octal & Custom Bases
Octal (base 8) was historically used in Unix file permissions and older computing systems. Custom bases from 2 to 36 are useful in specialised applications like URL shorteners (base 62) or mathematical exploration.
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