| Base | Representation | |
|---|---|---|
| Binary (2) | – | |
| Octal (8) | – | |
| Decimal (10) | – | |
| Hexadecimal (16) | – |
How to use the Number Base Converter
- Select the base of the number you are entering, Decimal, Binary, Octal, or Hexadecimal.
- Type the number, the table updates instantly with all four representations.
- Click Copy next to any row to copy that value.
The four number bases explained
Binary (base 2) uses only digits 0 and 1. Every bit in a computer is a binary digit. Binary is the native representation of digital circuits, memory addresses, and bitwise operations.
Octal (base 8) uses digits 0-7. Three binary digits map exactly to one octal digit, making it a compact shorthand for binary. Octal is best known for Unix file permissions: chmod 755 means 111 101 101 in binary (rwxr-xr-x).
Decimal (base 10) uses digits 0-9. It is the number system humans use in everyday life. All other bases are ultimately converted to decimal for human interpretation.
Hexadecimal (base 16) uses digits 0-9 and letters A-F. Four binary digits map to one hex digit, making hex an extremely compact binary representation. It appears everywhere in computing: memory addresses (0x7FFE4A3C), CSS colors (#FF5733), byte sequences, and binary file editors.
Conversion table: 0-15
| Decimal | Binary | Octal | Hex |
|---|---|---|---|
| 0 | 0000 | 0 | 0 |
| 5 | 0101 | 5 | 5 |
| 10 | 1010 | 12 | A |
| 15 | 1111 | 17 | F |
| 16 | 10000 | 20 | 10 |
| 255 | 11111111 | 377 | FF |
Common use cases
- Bitwise operations: convert to binary to visualize AND, OR, XOR, and bit shift results
- Color codes: CSS hex colors are two-digit hex values per channel:
#RRGGBB - Network and memory: IP addresses, MAC addresses, and memory offsets are often written in hex
- File permissions: Unix permission values like 755 or 644 are octal numbers