Octal to Binary
Convert an octal number to its binary (base-2) value.
About the Octal to Binary converter
This tool expands an octal number into binary. Because octal is base-8, each octal digit corresponds to exactly three binary digits, so 32 becomes 011 010, written as 11010. This makes it a fast way to unpack a compact octal value, such as a Unix permission code, into the underlying bit pattern.
How to use it
- Enter an octal number using only the digits 0 to 7.
- The binary equivalent appears straight away.
- Copy the result for a circuit, bit mask, or learning exercise.
A typical use is seeing the exact bits behind a permission value like 644. The converter treats the input as an unsigned whole number and handles long values exactly, so large numbers convert without rounding. Inputs containing an 8 or 9 are not valid octal and will not convert. Everything runs in your browser, so the numbers you enter are never uploaded.
Frequently asked questions
How many binary digits does each octal digit become?
Each octal digit expands to exactly three binary digits, because octal is base-8 and 8 equals 2 to the third power.
Why will my input not convert?
Octal uses only the digits 0 through 7. If your number contains an 8 or 9 it is not valid octal and cannot be converted.
Does it handle large octal numbers?
Yes. The conversion uses exact integer arithmetic, so even long octal values convert without losing precision.
Is my input sent to a server?
No. The conversion runs in your browser, so your numbers stay on your device.