Octal to Decimal Converter
Type a octal number of any length to see it in decimal, with every step of the working.
Octal to decimal table
| Octal | Decimal |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
| 4 | 4 |
| 5 | 5 |
| 7 | 7 |
| 10 | 8 |
| 12 | 10 |
| 17 | 15 |
| 20 | 16 |
| 40 | 32 |
| 100 | 64 |
| 144 | 100 |
| 177 | 127 |
| 200 | 128 |
| 377 | 255 |
| 400 | 256 |
| 1750 | 1000 |
| 2000 | 1024 |
Worked examples
10 in decimal
12 (octal)
10 (decimal)
Decimal value 10.
255 in decimal
377 (octal)
255 (decimal)
Decimal value 255.
2026 in decimal
3752 (octal)
2026 (decimal)
Decimal value 2026.
About Octal to Decimal Converter
This converter turns octal numbers into decimal and shows how. To convert octal to decimal, multiply each octal digit by its place value, which is a power of 8, and add the results. For example, 12 in octal is 10 in decimal, and 3752 is 2026.
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. Decimal is the base 10 system we count in every day, with place values of ones, tens, hundreds and so on. Numbers of any length are converted exactly, because the tool works with whole numbers digit by digit instead of rounding.
How to use Octal to Decimal Converter
- Type or paste a octal number into the first box. Spaces, underscores and prefixes such as 0x are ignored.
- Read the decimal 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 decimal back to octal.
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 octal to decimal by hand?
Multiply each octal digit by its place value, which is a power of 8, and add the results. The working table on this page shows exactly these steps for the number you type.
What is 377 in decimal?
377 in octal is 255 in decimal. In decimal it is 255, the largest number that fits in one byte.
What is 3752 in decimal?
3752 in octal is 2026 in decimal.
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.