Number Base Converter
Convert numbers between base 2 (binary), base 8 (octal), base 10 (decimal), and base 16 (hexadecimal). Includes an interactive ASCII reference table.
| Decimal | Binary | Octal | Hex |
|---|---|---|---|
| 0 | 0 | 0 | 0 |
| 1 | 1 | 1 | 1 |
| 8 | 1000 | 10 | 8 |
| 10 | 1010 | 12 | A |
| 16 | 10000 | 20 | 10 |
| 32 | 100000 | 40 | 20 |
| 64 | 1000000 | 100 | 40 |
| 127 | 1111111 | 177 | 7F |
| 128 | 10000000 | 200 | 80 |
| 255 | 11111111 | 377 | FF |
How to Use the Number Base Converter
- Enter a number in any supported base
- Select the input base (binary, octal, decimal, or hexadecimal)
- See the number converted to all bases simultaneously
- View the binary bit visualization for a visual breakdown
- Check the ASCII character if the value is 0-127
Popular Conversions
ASCII Table
Browse all 128 ASCII character codes with decimal, binary, octal, and hexadecimal values.
What Is a Number Base Converter?
A number base converter translates values between different positional numeral systems — such as binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16). Each base uses a different set of digits to represent quantities, and converting between them is a fundamental task in computer science, networking, and digital electronics.
Binary is the native language of computers, hexadecimal provides a compact way to represent binary data, and octal was historically used in Unix file permissions. Our converter handles conversions instantly, displays results in all supported bases simultaneously, and includes a full ASCII reference table for looking up character codes.
Popular Use Cases
Programming and Debugging
Convert between hex, binary, and decimal when reading memory addresses, debugging bitwise operations, or interpreting color codes like #FF5733.
Networking and IP Addresses
Translate subnet masks and IP addresses between decimal and binary to understand network segmentation and CIDR notation.
Digital Electronics
Work with binary values when designing logic circuits, reading datasheets, or programming microcontrollers and FPGAs.
Cryptography and Encoding
Convert data between hex and other representations commonly used in hash outputs, encryption keys, and encoding schemes.
Tips for Working with Number Bases
Memorize Hex Digits 0-F
Hex uses 0-9 and A-F where A=10, B=11, C=12, D=13, E=14, F=15. Knowing these by heart makes reading hex dumps and color codes instant.
Group Binary Digits by Four
Each group of four binary digits maps to exactly one hex digit. For example, 1010 1111 = AF. This makes binary-to-hex conversion trivial to do mentally.
Use Standard Prefixes
In code, prefix binary with 0b (0b1010), octal with 0o (0o12), and hex with 0x (0x0A). This prevents ambiguity about which base a number is written in.
Learn Key ASCII Values
Knowing that A=65 (0x41), a=97 (0x61), 0=48 (0x30), and space=32 (0x20) helps you quickly decode ASCII data in hex editors and network captures.