Number Base Converter
Convert between binary, octal, decimal, and hex. Free, no signup.
How It Works
Enter a number, select its base, and click Convert. The number is displayed in all four bases: binary, octal, decimal, and hexadecimal. Click any result to copy it.
What Are Number Bases?
Number bases (or radixes) define how many digits a numbering system uses. Decimal uses 0-9, binary uses 0-1, octal uses 0-7, and hexadecimal uses 0-9 and A-F. Binary is used in computing, hex is common in colors and memory addresses, and octal appears in Unix file permissions.
Common Conversions
The table below shows how the same values look across all four bases. It is handy for spotting patterns — every hex digit maps to exactly four binary digits, and each octal digit maps to three.
| Decimal | Binary | Octal | Hex |
|---|---|---|---|
| 8 | 1000 | 10 | 8 |
| 10 | 1010 | 12 | A |
| 16 | 10000 | 20 | 10 |
| 64 | 1000000 | 100 | 40 |
| 255 | 11111111 | 377 | FF |
| 1024 | 10000000000 | 2000 | 400 |
Where You Use Each Base
Programmers reach for hexadecimal to write color codes like #FF8800, memory addresses, and byte values, since two hex digits fit one byte. Binary shows the raw bits behind a value, octal encodes Unix file permissions such as 755, and decimal is the everyday base we count in. Converting between them is a daily task in coding, networking, and electronics.
Frequently Asked Questions
How do I convert a number between binary, decimal, hex, and octal?
Type the number, choose the base it is currently in (decimal, binary, octal, or hexadecimal), and click Convert. The tool immediately shows the same value in all four bases so you can read off whichever one you need. Click any result to copy it to your clipboard.
How do I enter and read hexadecimal numbers?
Select Hexadecimal as the input base and type digits 0-9 and letters A-F (case does not matter). Hexadecimal results are shown in uppercase, so a decimal 255 appears as FF and a decimal 4095 appears as FFF.
Can it convert numbers with a decimal point or fraction?
No. The converter works with whole numbers only. It reads the integer part of what you enter and ignores anything after a decimal point, so 12.75 is treated as 12. For fractional binary or hex conversions you would need a specialized calculator.
Is there a limit on how large a number I can convert?
You can convert very large whole numbers, but because the tool uses standard JavaScript numbers, values above about 9 quadrillion (2 to the 53rd power) may lose precision in the last digits. For everyday programming and networking values this is never an issue.
Is the converter free and private?
Yes. It is completely free with no signup, and every conversion runs in your browser with JavaScript. Nothing you type is uploaded, logged, or stored anywhere.