OCT2BIN Function in Excel: Octal to Binary

OCT2BIN Function in Excel: Octal to Binary 1
⏱ 1 min readUpdated 5 October 2026

EngineeringLevel: ExpertAvailable in: Excel 2007+

In this article
  1. Syntax
  2. Examples
  3. Example 1
  4. OCT2BIN in practice
  5. Where you will use it
  6. Worked example
  7. Mistakes people make
  8. Related functions

OCT2BIN converts a octal number to binary. Used for device codes, permission bits, memory addresses and number-system lessons.

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Syntax

=OCT2BIN(number, [places])
Argument What it means
number Octal number (as text or a number)
places Pad with leading zeros to this length

Examples

Example 1

=OCT2BIN(A2)

Result: 111. See the worked example table below for more cases.

OCT2BIN in practice

Where you will use it

  • Reading octal values from device or network logs
  • Teaching number systems
  • Converting codes for systems that expect binary

Worked example

InputFormulaResult
7=OCT2BIN(A2)111
17=OCT2BIN(A3)1111
777=OCT2BIN(A4)111111111

Results calculated in Excel.

Mistakes people make

MistakeWhat to do instead
Input too long or invalid digits#NUM!; check the digits allowed in the base
Negative resultsLarge inputs use two's complement (10 characters)

BASE · DECIMAL

📚 Part of the free Excel course: Beginner → Expert · Try it in the Formula Lab or ask the AI Helper.

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