Convert binary to octal (base 2 → base 8)
Use this converter when you have binary integers (base 2) and want the octal representation (base 8).
This page is a focused Binary → Octal variant built for speed:
- Batch mode is enabled by default (one value per line)
- Controls are intentionally hidden to keep this variant fast and distraction-free
Need decimal/hex too, swapping, or formatting options? Open the full Number Base Converter.
How to use it
- Paste your binary values into the input (left).
- Use one number per line.
- Copy the octal results from the output (right).
Signed values are supported:
-1001→-11+11111111→377
Input rules (binary)
Allowed characters
Binary input may contain only:
0and1- an optional leading
+or-
Examples:
0101010-101010
Optional 0b prefix
You may paste values like:
0b11110000-0b1011
Separators are ignored
Spaces and underscores are ignored, so these are valid:
1111_00000b1111 0000
Output format (octal)
- Output uses digits
0–7 - Negative values keep a leading
- - No
0oprefix by default
Examples:
1010→1211111111→37710000000000→2000-1001→-11
Quick mental check (why octal maps nicely)
Octal is convenient because it groups binary digits in chunks of 3:
101 010(binary) →5 2(octal) →52
You don’t need to do this manually — the converter does it — but it helps explain why this mapping is common.
Batch example (one per line)
Input (binary):
1010
11111111
10000000000
-1001
0b1111 0000
2Output (octal):
12
377
2000
-11
360
!ERROR: Binary input may contain only 0 and 1
One invalid line won’t break the rest.Common use cases
Unix permissions and bit fields
Octal is widely used to represent permission bits (like 755), because each digit corresponds to 3 bits.
Compact representation for large binaries
Octal is shorter than binary but still maps cleanly to it, making it helpful for quick inspection.
Embedded/digital logic learning
Binary → octal conversion shows how different base systems represent the same underlying value.
Troubleshooting
“Binary input may contain only 0 and 1”
A line includes an invalid character (like 2, 8, A, ., or commas).
Remove invalid characters, or switch bases in the full tool if your input isn’t actually binary.
Notes
- This is number base conversion for integers, not text/byte encoding.
- Everything runs locally in your browser — nothing is uploaded.
