Number Base Converter
Convert between binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16) in real time.
11111111
377
255
FF
Quick Reference (0–15)
| DEC | HEX | BIN | OCT |
|---|---|---|---|
| 0 | 0 | 0000 | 0 |
| 1 | 1 | 0001 | 1 |
| 2 | 2 | 0010 | 2 |
| 3 | 3 | 0011 | 3 |
| 4 | 4 | 0100 | 4 |
| 5 | 5 | 0101 | 5 |
| 6 | 6 | 0110 | 6 |
| 7 | 7 | 0111 | 7 |
| 8 | 8 | 1000 | 10 |
| 9 | 9 | 1001 | 11 |
| 10 | A | 1010 | 12 |
| 11 | B | 1011 | 13 |
| 12 | C | 1100 | 14 |
| 13 | D | 1101 | 15 |
| 14 | E | 1110 | 16 |
| 15 | F | 1111 | 17 |
What Are Number Bases?
A number base (or radix) defines how many unique digits a positional numeral system uses. Decimal (base 10) is the everyday system with digits 0–9. Binary (base 2) uses only 0 and 1, making it the native language of computers. Octal (base 8) uses digits 0–7 and was popular in early computing. Hexadecimal (base 16) uses 0–9 and A–F and is widely used in programming, memory addresses, and color codes.
How to Use the Base Converter
Enter any number in the input field and choose its original base. The tool instantly shows the same value expressed in all four bases simultaneously. Each output field has a copy button. Only valid digits for the selected base are accepted — for example, binary mode only allows 0 and 1. The quick reference table below shows values 0–15 side by side in all four bases.
Common Use Cases
Binary conversion is essential when working with bitwise operations, flags, and low-level programming. Hexadecimal is used in CSS color codes (#FF5733), memory addresses (0x1A2B), and debugging. Octal appears in Unix file permissions (chmod 755) and some assembly languages. Understanding all four bases is a fundamental skill for software developers and system engineers.
Quick Examples
- 255 decimal = FF hex = 11111111 binary = 377 octal
- 16 decimal = 10 hex = 10000 binary = 20 octal
- 10 decimal = A hex = 1010 binary = 12 octal
- 42 decimal = 2A hex = 101010 binary = 52 octal
- 256 decimal = 100 hex = 100000000 binary = 400 octal