Converts an octal number to binary.

If this function is not available, and returns the #NAME? error, install and load the Analysis ToolPak add-in.


  1. On the Tools menu, click Add-Ins.
  2. In the Add-Ins available list, select the Analysis ToolPak box, and then click OK.
  3. If necessary, follow the instructions in the setup program.



Number     is the octal number you want to convert. Number may not contain more than 10 characters. The most significant bit of number is the sign bit. The remaining 29 bits are magnitude bits. Negative numbers are represented using two's-complement notation.

Places     is the number of characters to use. If places is omitted, OCT2BIN uses the minimum number of characters necessary. Places is useful for padding the return value with leading 0s (zeros).


  • If number is negative, OCT2BIN ignores places and returns a 10-character binary number.
  • If number is negative, it cannot be less than 7777777000, and if number is positive, it cannot be greater than 777.
  • If number is not a valid octal number, OCT2BIN returns the #NUM! error value.
  • If OCT2BIN requires more than places characters, it returns the #NUM! error value.
  • If places is not an integer, it is truncated.
  • If places is nonnumeric, OCT2BIN returns the #VALUE! error value.
  • If places is negative, OCT2BIN returns the #NUM! error value.


The example may be easier to understand if you copy it to a blank worksheet.

ShowHow to copy an example

  1. Create a blank workbook or worksheet.
  2. Select the example in the Help topic.

 Note   Do not select the row or column headers.

Selecting an example from Help

Selecting an example from Help
  1. Press CTRL+C.
  2. In the worksheet, select cell A1, and press CTRL+V.
  3. To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Formulas tab, in the Formula Auditing group, click the Show Formulas button.
Formula Description (Result)
=OCT2BIN(3, 3) Converts octal 3 to binary with 3 characters (011)
=OCT2BIN(7777777000) Converts octal 7777777000 to binary (1000000000)
Applies to:
Excel 2003