Converter
Binary, Octal, Decimal, Hex & Every Base In Between
Convert any value between base 2 and base 60
Results are provided for informational purposes only and may contain errors. Please verify important information independently. Use of this tool is at your own risk.
How to convert decimal to octal
Convert decimal numbers to octal instantly: type a value and the octal result appears as you type. Below the converter you'll find the method to do it by hand, a worked example and a table of common values.
- Type or paste a decimal number into the box above. Negative numbers and fractions work too.
- The From and To bases are already set to decimal and octal, so the result appears right away: 511 becomes 777.
- Copy the result, or choose any other base from 2 to 60 to convert the same value.
Converting decimal to octal by hand
Divide the number by 8 and write down the remainder. Keep dividing the result by 8 until it reaches 0. The remainders, read from the last one to the first, are the octal digits. To check the answer, multiply each digit by its place value and add them up:
777₈ = 7·8² + 7·8¹ + 7·8⁰= 448 + 56 + 7 = 511₁₀
Decimal to octal table
| Decimal | Octal |
|---|---|
0 | 0 |
1 | 1 |
2 | 2 |
7 | 7 |
8 | 10 |
10 | 12 |
15 | 17 |
16 | 20 |
42 | 52 |
64 | 100 |
100 | 144 |
127 | 177 |
255 | 377 |
256 | 400 |
1000 | 1750 |
1024 | 2000 |
Decimal and octal explained
Decimal is base 10, the everyday number system with the digits 0 to 9. Each position is worth ten times the one to its right.
Octal is base 8, with the digits 0 to 7. Each octal digit stands for exactly three bits, which is why Unix file permissions such as 755 are written in octal.
Frequently asked questions
Can I convert negative numbers and fractions?
Yes. Put a minus sign in front of a negative number and use a point for the fraction, for example -12.5. A fraction that never ends in octal is cut off after 32 digits.
How large can the number be?
There is no practical limit. The converter uses exact whole-number arithmetic, so even numbers with hundreds of digits are converted without rounding.
Do uppercase and lowercase letters matter?
Not up to base 36: FF and ff are the same hexadecimal number. From base 37 upward, uppercase and lowercase letters are different digits.
Is this tool free?
Yes, it's free to use. No signup, no email required. Get results on this page.
How do I get my result?
Use the tool on this page. Your result appears here; no email delivery is required.