Decimal to Octal

Enter a decimal number and convert it to octal, hexadecimal, and binary. Results appear instantly in your browser.

Decimal
Valid: 0-9 (integers)
Octal (Base 8)
Result will appear here
Hexadecimal (Base 16)
—
Binary (Base 2)
—
Quick Reference
0→0
1→1
7→7
8→10
15→17
16→20
64→100
255→377
493→755
511→777

Decimal to Octal Converter

This tool converts decimal (base 10) numbers into their octal (base 8), hexadecimal (base 16), and binary (base 2) equivalents. It is useful when setting Unix file permissions, working with legacy systems, or studying number system conversions.

The conversion runs entirely in your browser using JavaScript's BigNumber library for precision.

How to use

  1. Type or paste a decimal number into the input field (e.g. 255 or 493).
  2. Click Convert to see the octal, hexadecimal, and binary results.
  3. Use the Copy button to copy the octal result to your clipboard.
  4. Click Clear to reset all fields.

What is octal?

Octal is a base 8 number system using the digits 0 through 7. It is used in computing as a compact representation of binary numbers — each octal digit corresponds to three binary digits. Unix file permissions, for example, are commonly expressed in octal (e.g. 755 means read/write/execute for owner, read/execute for group and others).

Example

Decimal:     493
Octal:       755
Hexadecimal: 1ED
Binary:      111101101