Decimal to Octal Converter
Type a decimal number of any length to see it in octal, with every step of the working.
Decimal to octal table
| Decimal | Octal |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
| 4 | 4 |
| 5 | 5 |
| 7 | 7 |
| 8 | 10 |
| 10 | 12 |
| 15 | 17 |
| 16 | 20 |
| 32 | 40 |
| 64 | 100 |
| 100 | 144 |
| 127 | 177 |
| 128 | 200 |
| 255 | 377 |
| 256 | 400 |
| 1000 | 1750 |
| 1024 | 2000 |
Worked examples
10 in octal
10 (decimal)
12 (octal)
Decimal value 10.
255 in octal
255 (decimal)
377 (octal)
Decimal value 255.
2026 in octal
2026 (decimal)
3752 (octal)
Decimal value 2026.
About Decimal to Octal Converter
This converter turns decimal numbers into octal and shows how. To convert decimal to octal, divide the number by 8 again and again, writing down each remainder, then read the remainders from last to first. For example, 10 in decimal is 12 in octal, and 2026 is 3752.
Decimal is the base 10 system we count in every day, with place values of ones, tens, hundreds and so on. Octal packs three bits into each digit. It is best known today from Unix file permissions, where 755 means read, write and execute for the owner and read and execute for everyone else. Numbers of any length are converted exactly, because the tool works with whole numbers digit by digit instead of rounding.
How to use Decimal to Octal Converter
- Type or paste a decimal number into the first box. Spaces, underscores and prefixes such as 0x are ignored.
- Read the octal result straight away in the second box, grouped for easier reading if you leave the box ticked.
- Look at the working table to see each step of the method.
- Copy the result, or use the swap button to convert octal back to decimal.
Common uses
- Setting Unix and Linux file permissions such as 755 or 644
- Reading older computing documentation
- Computer science homework on number bases
- Checking escape codes in some programming languages
Frequently asked questions
How do I convert decimal to octal by hand?
Divide the number by 8 again and again, writing down each remainder, then read the remainders from last to first. The working table on this page shows exactly these steps for the number you type.
What is 255 in octal?
255 in decimal is 377 in octal. In decimal it is 255, the largest number that fits in one byte.
What is 2026 in octal?
2026 in decimal is 3752 in octal.
Can it convert very large numbers?
Yes. Whole numbers with up to 4,096 digits are converted exactly. The working table shows the first rows when a number is very long.
Does it handle fractions or negative numbers?
Negative whole numbers are converted with their minus sign kept. Fractions are not supported, because many fractions that end in one base repeat for ever in another.