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Binary to Octal

Convert binary to octal — bits collapse into base-8 digits, 3 at a time.

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Updated Sep 2026

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How to use Binary to Octal

  1. Paste the binary value — e.g. 111101101, or several values separated by spaces.
  2. Read the octal instantly: 111101101 → 755.
  3. For chmod work, write your three permission triplets as bits first (rwx = 111), then read the octal off the output.
  4. Click “Copy result” to take the value into your terminal or notes.

What is Binary to Octal?

A binary to octal converter compresses a base-2 number into base 8 by grouping bits in threes from the right and replacing each triplet with one digit: 111 101 101 becomes 755. Three bits hold exactly eight combinations, one per octal digit, so the conversion is mechanical — no division, just grouping.

It is the reverse view of the Unix permissions story: if you know which permission bits you want set, grouping them in threes hands you the chmod number. Want owner rwx, group r--, others nothing? 111 100 000 → 740 — done.

About the Binary to Octal

Paste a binary value and its octal form appears instantly; space-separated values convert independently and BigInt math keeps any length exact.

Practical jobs: turning a desired permission bit pattern into the chmod octal (110 110 100 → 664, the standard for shared group files), compacting digital-logic homework answers, and reading legacy octal-based formats or core dumps from systems that predate hex's dominance. Anything besides 0s and 1s in the input is flagged with the exact bad token.

Runs entirely in your browser. Octal to Binary reverses the direction; Binary to Hex does the same compression with 4-bit groups instead of 3.

Frequently Asked Questions

Group bits into threes from the right, pad the leftmost group with zeros, then read each group as 0–7: 1111 → 001 111 → 17.
Write each triplet as bits — r=4, w=2, x=1 positions: rw- r-- r-- → 110 100 100 → 644. Owner, group, others, in that order.
The group size is the base's power of two: 8 = 2³ (three bits), 16 = 2⁴ (four bits). Both let you convert by lookup instead of arithmetic — decimal (not a power of 2) never gets that shortcut.
Group from the right: 10 110 011 → pad → 010 110 011 → 263. The same byte in hex is B3 and in decimal 179 — one value, four notations.
Yes — always group from the right, where the 1s place is. Grouping 1111 from the left as 111|1 would misread it; from the right it is 1|111 → 001 111 → 17.

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