The Excel DEC2OCT function converts a decimal number to its octal equivalent.
Syntax: =DEC2OCT (number, [places])
The DEC2OCT function syntax has the following arguments:
 Number Required. The decimal integer you want to convert. If number is negative, places is ignored and DEC2OCT returns a 10character (30bit) octal number in which the most significant bit is the sign bit. The remaining 29 bits are magnitude bits. Negative numbers are represented using two’scomplement notation.

Places Optional. The number of characters to use. If places is omitted, DEC2OCT uses the minimum number of characters necessary. Places is useful for padding the return value with leading 0s (zeros).
Example: Let’s look at some Excel DEC2OCT function examples and explore how to use the DEC2OCT function as a worksheet function in Microsoft Excel:
Syntax: =DEC2OCT(A2)
Result:
Based on the Excel spreadsheet above, the following DEC2OCT examples would return:
Syntax: =DEC2OCT(A3)
Result: 144
Syntax: =DEC2OCT(A4)
Result: 37
Syntax: =DEC2OCT(A5)
Result: 7777777770
Syntax: =DEC2OCT(A6)
Result: 310
Syntax: =DEC2OCT(A7)
Result: 1
Syntax: =DEC2OCT(A8)
Result: 3777777777
Syntax: =DEC2OCT(A9)
Result: #NUM!
Syntax: =DEC2OCT(A10)
Result: 257741
Syntax: =DEC2OCT(A11,B11)
Result: 072
Syntax: =DEC2OCT(A12,B12)
Result: 0000000010
Syntax: =DEC2OCT(A13,B13)
Result: 011
Syntax: =DEC2OCT(A14,B14)
Result: 0031
Syntax: =DEC2OCT(A15,B15)
Result: 00000016
Note:
 If number < 536,870,912 or if number > 536,870,911, DEC2OCT returns the #NUM! error value.
 If number is nonnumeric, DEC2OCT returns the #VALUE! error value.
 If DEC2OCT requires more than places characters, it returns the #NUM! error value.
 If places is not an integer, it is truncated.
 If places is nonnumeric, DEC2OCT returns the #VALUE! error value.

If places is negative, DEC2OCT returns the #NUM! error value.