Binary to Octal Converter
Type a binary number of any length to see it in octal, with every step of the working.
Binary to octal table
| Binary | Octal |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 10 | 2 |
| 11 | 3 |
| 100 | 4 |
| 101 | 5 |
| 111 | 7 |
| 1000 | 10 |
| 1010 | 12 |
| 1111 | 17 |
| 10000 | 20 |
| 100000 | 40 |
| 1000000 | 100 |
| 1100100 | 144 |
| 1111111 | 177 |
| 10000000 | 200 |
| 11111111 | 377 |
| 100000000 | 400 |
| 1111101000 | 1750 |
| 10000000000 | 2000 |
Worked examples
10 in octal
1010 (binary)
12 (octal)
Decimal value 10.
255 in octal
11111111 (binary)
377 (octal)
Decimal value 255.
2026 in octal
11111101010 (binary)
3752 (octal)
Decimal value 2026.
About Binary to Octal Converter
This converter turns binary numbers into octal and shows how. To convert binary to octal, split the bits into groups of 3 from the right and replace each group with one octal digit. For example, 1010 in binary is 12 in octal, and 11111101010 is 3752.
Binary is the language of computers: every value in memory is a pattern of bits, each one a 0 or a 1. 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 Binary to Octal Converter
- Type or paste a binary 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 binary.
Common uses
- Reading or setting bit flags and permissions in software
- Working out subnet masks and IP address ranges
- Computer science and GCSE or A level homework
- Checking how a number is stored in memory
Frequently asked questions
How do I convert binary to octal by hand?
Split the bits into groups of 3 from the right and replace each group with one octal digit. The working table on this page shows exactly these steps for the number you type.
What is 11111111 in octal?
11111111 in binary is 377 in octal. In decimal it is 255, the largest number that fits in one byte.
What is 11111101010 in octal?
11111101010 in binary 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.