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The Excel OCT2DEC Function
Related Function:
Dec2Oct FunctionBasic Description
Hexadecimal (base 16), decimal (base 10), octal (base 8), and binary (base 2) are the most commonly used numeral systems in engineering and computing. Therefore, Excel has provided functions to convert numeric values to and from each of these systems.
The Excel Oct2Dec function converts an Octal (a base8 number) into a decimal number.
The format of the function is :
OCT2DEC( number )
Where the number argument is the octal number that is to be converted to decimal.
Note that the supplied number argument must not be more than 10 characters (40 bits) long. The most significant bit of this value denotes the sign of the number and the remaining 39 bits denote the magnitude. Negative numbers are represented using two's complement notation.
+ Display Octal Summary:
Octal
The Octal (Base 8) Numeral System uses the digits 07.
The following table shows the first 16 octal values, along with the equivalent decimal values:
Octal  1  2  3  4  5  6  7  10  11  12  13  14  15  16  17  20 
Decimal  1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16 
For further information on the octal numeral system, see the
Wikipedia Octal PageOct2Dec Function Examples
The following spreadsheet shows examples of the Excel Oct2Dec function.
Formulas:  A 

1  =OCT2DEC( "10" ) 

2  =OCT2DEC( "22" ) 

3  =OCT2DEC( "0000000010" ) 

4  =OCT2DEC( "7777777770" ) 

5  =OCT2DEC( "355" ) 

 Results:  A  B 

1  8  Result is 1*8 + 0 

2  18  Result is 2*8 + 2 

3  8  Result is 1*8 + 0 

4  8  Result is 8^9 + 7*8^8 + 7*8^7 + ... + 7*8 + 0 

5  237  Result is 3*8^2 + 5*8 + 5 


Note that, in the above example spreadsheet, the negative octal in cell A4 is represented by two's complement notation.
Further information and examples of the Excel Oct2Dec function can be found on the Microsoft Office website.
Oct2Dec Function Errors
If you get an error from your Excel Oct2Dec function this is likely to be one of the following :
Common Errors
#NUM!    Occurs if the supplied Number argument is not recognised as a octal number, or contains more than 10 characters 
#NAME?    Occurs when Analysis ToolPak addin is not enabled in your Excel. You will need to enable the addin if you want to use the Excel engineering functions.
+ Show How to Do This in Excel 2003:
 From the Tools dropdown menu, select the option AddIns ...
 An 'AddIns' window will pop up. From this, select the option Analysis ToolPak and click OK
+ Show How to Do This in Excel 2007:
 Click the Microsoft button on the top left of your spreadsheet and select
the Excel Options button
 From the menu on the left hand side, select AddIns
 In the 'Manage:' box, select Excel Addins and click Go...
 An 'AddIns' window will pop up. From this, select the option Analysis ToolPak and click OK
+ Show How to Do This in Excel 2010 or Excel 2013:
 Click the File tab (top left of your spreadsheet) and select Options
 From the menu on the left hand side, select AddIns
 If the window that pops up doesn't show the 'Addins' list, use the 'Manage:'
dropdown menu (at the bottom of the window) to select Excel Addins. Click Go...
 From the 'AddIns' window, select the option Analysis ToolPak and click OK
