Convert numbers between binary, decimal, octal and hexadecimal instantly. Type in any field and all others update automatically.
Computers work in binary - base 2 - using only 0s and 1s. But humans prefer decimal - base 10. Hexadecimal - base 16 - is a compact way to represent binary that is widely used in programming for memory addresses, colour codes, and byte values. Octal - base 8 - is used in Unix file permissions and some older systems.
Understanding how to convert between these bases is a fundamental skill for developers working close to the hardware, writing systems code, or debugging binary data.
Each hex digit represents exactly 4 binary bits. So two hex digits represent one byte. This makes hex a compact and readable way to work with binary data. Memory addresses, colour codes like #FF5733, and byte sequences are all commonly written in hex.
Octal is most commonly used in Unix and Linux file permissions. The permission value 755 is an octal number meaning owner can read/write/execute, group and others can read/execute.