binary to octal

Binary to Octal Converter

Each octal digit equals exactly 3 binary bits: 111₂ = 7₈. Unix permissions (chmod 755) use octal.

Number to convert0–9

Source base

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Octal and Unix permissions

chmod 755 means: owner=7 (rwx), group=5 (r-x), others=5 (r-x). In binary: 111 101 101 = 0755₈.
The 0o prefix distinguishes octal from decimal in modern languages like JavaScript, Python, and Rust.

Examples

chmod 755

Input: 111101101₂
Expected output: 0o755

rwxr-xr-x Unix permission.

chmod 644

Input: 110100100₂
Expected output: 0o644

rw-r--r-- — default for files.

Full tool FAQ

What is number base conversion?

Converting a number between bases means representing the same value using a different set of digits. A decimal (base 10) number can be expressed exactly in binary (base 2), hexadecimal (base 16), or any other base.

Why is hexadecimal so common in computing?

How do you convert binary to decimal manually?

Does the tool support negative numbers?

What is the maximum number size?

Which bases are supported?

What is base 36?

Are calculations done on the server?

Frequently asked questions

When to use octal instead of hex?

Octal is preferred in Unix contexts (permissions, syscalls). Hex is the standard for memory, colors, and network protocols.

Does this page replace official or professional review?

No. It helps explain the scenario and use the tool more safely, but real decisions should consider official sources, full context and qualified guidance when needed.