Number Base Converter (Binary, Hex, Decimal)
Convert numbers between decimal, binary, octal and hexadecimal live.
Updated June 2026
Type a number in any field — the other three update live. Hex is shown in uppercase. A leading minus sign is supported.
How to use the Number Base Converter (Binary, Hex, Decimal)
- 1
Pick a field
Choose Decimal, Binary, Octal or Hex and type or paste your number there.
- 2
Watch the rest update
The other three bases convert instantly. Invalid digits show a subtle inline note.
- 3
Copy any result
Use the Copy button on each field to grab the converted value.
About this tool
A number base (or radix) is how many distinct digits a numeral system uses. Decimal is base 10, binary is base 2, octal is base 8, and hexadecimal is base 16. The same value can be written in any of them — for example, 255 in decimal is 11111111 in binary, 377 in octal, and FF in hexadecimal. This number base converter shows all four at once.
Edit any field — decimal, binary, octal or hex — and the other three update live as you type. If you enter a digit that is not valid for that base (say, a 2 in the binary field), the tool shows a subtle inline note and leaves the other fields untouched, so you never lose your place. Hexadecimal output is shown in uppercase, the convention used in most color codes and memory dumps.
Conversions use big-integer math internally, so very large values stay exact instead of rounding the way floating-point numbers would. Everything runs in your browser, which makes it safe and fast for reading hex dumps, debugging bitmasks, decoding color values, and working through computer-science exercises.
Examples
Input
Decimal 255
Output
Binary 11111111, Octal 377, Hex FF
Input
Hex 1A
Output
Decimal 26, Binary 11010, Octal 32
Input
Binary 1010
Output
Decimal 10, Octal 12, Hex A
Common uses
- Programmers converting a hex color code or memory address to decimal and back
- Students working through binary, octal and hexadecimal exercises for a CS course
- Embedded developers decoding register values and bitmasks written in hex
- Anyone reading a hex dump and needing the decimal value of a byte
- Network engineers converting between binary and decimal for subnet math
- Developers translating between hex constants (0xFF) and the decimal literals their code expects
Frequently asked questions
Which bases can it convert between?+
Decimal (base 10), binary (base 2), octal (base 8) and hexadecimal (base 16). Edit any one and the other three update live.
Is hexadecimal shown in uppercase or lowercase?+
Uppercase, for example FF or 1A3. This matches the convention used in color codes, memory addresses and most documentation.
Can it handle very large numbers?+
Yes. Conversions use big-integer arithmetic, so large whole numbers stay exact and are not rounded like floating-point values would be.
What happens if I type an invalid digit?+
If a digit is not valid for the field's base — such as an 8 in the octal field — the tool shows a small inline note and leaves the other fields unchanged.
Does it support negative numbers?+
Yes. A leading minus sign is allowed and is carried through to every base. It works on whole integers.
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