01 BASES
Number Base Converter
Convert instantly between binary, octal, decimal, hexadecimal, and any custom base from 2 to 36. Type in any field to update all others.
Converter
Binary
Base 2
Octal
Base 8
Decimal
Base 10
Hexadecimal
Base 16
Custom base:
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Quick Reference
Common Values
| DEC | BIN | HEX |
| 0 | 0 | 0 |
| 8 | 1000 | 8 |
| 15 | 1111 | F |
| 16 | 10000 | 10 |
| 255 | 11111111 | FF |
| 256 | 100000000 | 100 |
| 1024 | 10000000000 | 400 |
| 65535 | 1111111111111111 | FFFF |
Hex Digits
| HEX | DEC | BIN |
| A | 10 | 1010 |
| B | 11 | 1011 |
| C | 12 | 1100 |
| D | 13 | 1101 |
| E | 14 | 1110 |
| F | 15 | 1111 |
About Number Bases
⬛ Binary (Base 2)
Uses only 0 and 1. The native language of digital circuits, CPUs, and memory. Every byte is 8 binary digits.
🔢 Octal (Base 8)
Uses digits 0–7. Common in Unix file permissions (e.g. chmod 755) and legacy systems. Each octal digit = 3 bits.
🔟 Decimal (Base 10)
The everyday number system using digits 0–9. All other bases are converted through decimal internally.
🟩 Hexadecimal (Base 16)
Uses 0–9 and A–F. Compact representation for binary data — widely used in colors, memory addresses, and encoding.
Related Tools
Frequently Asked Questions
Type your binary number into the Binary field above and the decimal result appears instantly. Manually, you multiply each bit by its positional power of 2 and sum the results — for example, 1010 = 1×8 + 0×4 + 1×2 + 0×1 = 10.
Hexadecimal (base 16) uses the digits 0–9 plus the letters A–F to represent values 10–15. It is compact — one hex digit represents exactly 4 binary bits, so a full byte (8 bits) is always two hex digits. This is why HTML colors like #FF5733 use hex.
Unix permissions are expressed as three octal digits: owner, group, and others. Each digit is the sum of read (4), write (2), and execute (1). So chmod 755 means owner=7 (rwx), group=5 (r-x), others=5 (r-x).
Any integer from 2 to 36 can be a number base. Base 36 uses all digits 0–9 and letters A–Z, producing very compact representations. Base 32 is common in encoding systems. This tool supports any custom base in that range.
This tool handles non-negative integers. For negative numbers, two's complement representation is the standard approach in computing — that's a separate topic best handled by a dedicated bitwise calculator. Floating-point base conversion is also outside the scope of this tool.