Number Base Converter
Convert numbers between binary, octal, decimal, and hexadecimal instantly.
Overview
A positional number system represents a value as a sum of digits multiplied by powers of its base. Binary uses base 2, octal base 8, decimal base 10 and hexadecimal base 16, with the letters A to F standing for the values ten to fifteen. The same quantity written in any of them is identical; only the notation changes.
Quick presets
Conversions
Common Values
| Decimal | Binary | Octal | Hex |
|---|---|---|---|
| 0 | 0 | 0 | 0 |
| 1 | 1 | 1 | 1 |
| 8 | 1000 | 10 | 8 |
| 16 | 10000 | 20 | 10 |
| 42 | 101010 | 52 | 2A |
| 255 | 11111111 | 377 | FF |
| 1024 | 10000000000 | 2000 | 400 |
| 65535 | 1111111111111111 | 177777 | FFFF |
Click a row to load that value.
Number Bases
- Binary (Base 2) — digits 0-1, used in computing
- Octal (Base 8) — digits 0-7, Unix file permissions
- Decimal (Base 10) — digits 0-9, everyday numbers
- Hexadecimal (Base 16) — digits 0-F, colors and memory addresses
How to Use
-
1
Enter the value
Type the amount you want to convert into the Number Base Converter.
-
2
Choose the units
Select the unit to convert from and the unit to convert to.
-
3
Read the converted value
The conversion updates instantly in your browser — no button, nothing sent to a server.
About
Hexadecimal is ubiquitous in computing because 16 is 2⁴, so each hex digit maps to exactly four binary digits with no arithmetic. A byte is two hex characters, which makes memory addresses, colour codes and hash values far more readable than the equivalent binary strings while preserving the bit structure.
Octal survives mainly in Unix file permissions, where three bits of read, write and execute map neatly onto a single digit, giving the familiar 755 and 644 modes. Conversion between any two bases proceeds through repeated division by the target base, reading the remainders in reverse.