- Character
- A
- Binary
- 01000001
- Hex
- 0x41
- Decimal
- 65
Free developer number converter
Binary Decimal Hex Converter
Convert unsigned integer values between binary, decimal, hexadecimal, and octal, then inspect simple byte values for ASCII and debugging work.
- Binary
- Decimal
- Hexadecimal
- Octal
Converted result
Base conversion
Input typedecimal input
- Binary
- 1111 1111
- Decimal
- 255
- Hexadecimal
- 0xFF
- Octal
- 0o377
- Bit length
- 8 bits
Byte helper
Inspect one byte
Enter a decimal byte from 0 to 255 to see its printable character, 8-bit binary value, hex value, and decimal value.
How base conversion works
A number base describes how many symbols are used to write a value. Decimal uses ten symbols, binary uses two, octal uses eight, and hexadecimal uses sixteen. The value is the same number, but the written representation changes.
For example, decimal 255 is binary 11111111, hexadecimal FF, and octal 377. Developers and network engineers switch between these formats when reading byte values, masks, flags, memory addresses, and protocol data.
Why hexadecimal is common
Hexadecimal is compact because one hex digit maps cleanly to four binary bits. That makes it easier to inspect binary data without reading a long string of ones and zeroes.
You see hex in color codes, MAC addresses, packet captures, hashes, byte dumps, memory addresses, and debugging output.
Binary, decimal, octal, and hex compared
Each base writes the same numeric value with a different set of symbols. The right display depends on what you are trying to inspect.
| Base | Symbols | Common use |
|---|---|---|
| Binary, base 2 | 0 and 1 | Bits, masks, flags, and low-level debugging. |
| Octal, base 8 | 0 through 7 | Unix permissions and compact legacy notation. |
| Decimal, base 10 | 0 through 9 | Human-readable counts and everyday arithmetic. |
| Hexadecimal, base 16 | 0-9 and A-F | Bytes, colors, memory, packet captures, and hashes. |
Common base prefixes
Programming tools often use a short prefix to show which base a number is written in. Prefixes are display hints; they do not change the underlying value.
| Prefix | Base | Example |
|---|---|---|
0b |
Binary | 0b1010 = 10 |
0o |
Octal | 0o12 = 10 |
| none | Decimal | 10 = 10 |
0x |
Hexadecimal | 0xA = 10 |
Binary and byte boundaries
Binary values are often grouped in fours or eights because that lines up with hex digits and bytes. This converter groups long binary output so the result is easier to scan.
The byte helper focuses on one 8-bit value at a time. Values from 32 through 126 are printable ASCII characters, while lower control values and higher extended byte values may not show as normal text.
Useful bit-width reference
When code, hardware, or a protocol expects a fixed width, leading zeroes can matter. Decimal 15 is still 15, but it may need to be displayed as 00001111 in an 8-bit field.
| Width | Maximum unsigned decimal | Maximum hex |
|---|---|---|
| 8-bit byte | 255 | 0xFF |
| 16-bit word | 65,535 | 0xFFFF |
| 32-bit unsigned | 4,294,967,295 | 0xFFFFFFFF |
| 64-bit unsigned | 18,446,744,073,709,551,615 | 0xFFFF...FFFF |
Common conversion mistakes
Common mistakes include confusing the written base with the actual value, dropping leading zeroes when a fixed byte width matters, or assuming every byte maps to a printable character. When exact width matters, keep track of whether you need 8-bit, 16-bit, 32-bit, or 64-bit output.
This tool focuses on unsigned whole numbers. Signed integers, negative values, and two's complement interpretation depend on the bit width and language or protocol rules, so verify those separately when debugging production code.