Number Base Converter
Convert between binary, octal, decimal, and hexadecimal — all four update as you type.
What Is a Number Base Converter?
A number base converter transforms numbers between different numeral systems. The four most common in computing are decimal (base-10), binary (base-2), hexadecimal (base-16), and octal (base-8). Enter a value in any base and the other three update instantly.
Understanding Number Bases
Decimal uses digits 0-9. Binary uses only 0 and 1 — how computers store all data. Hexadecimal uses 0-9 and A-F, where each hex digit equals 4 binary bits. Octal uses 0-7, commonly seen in Unix file permissions (755, 644).
Common Conversions
| Decimal | Binary | Hex | Octal |
|---|---|---|---|
| 10 | 1010 | A | 12 |
| 16 | 10000 | 10 | 20 |
| 255 | 11111111 | FF | 377 |
Frequently Asked Questions
Each binary digit = a power of 2. Binary 1010 = 1×8 + 0×4 + 1×2 + 0×1 = 10.
Base-16 using 0-9 and A-F. FF = 255 decimal = 11111111 binary.