# A to Z of Excel Functions: The BIN2OCT Function

6 January 2017

*Welcome back to our regular A to Z of Excel Functions blog. Today we look at the BIN2OCT function. *

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**The BIN2OCT function**

This function converts a binary number (base two) to an octal number (base eight).

The **BIN2OCT **function employs the following syntax to operate:

**BIN2OCT(number, [places])**

The **BIN2OCT** function has the following arguments:

**number:**this is required and represents the binary number you wish to convert. It should be noted that**number**cannot contain more than 10 characters (10 bits) and that the most significant bit of**number**is the sign bit. The remaining nine bits are magnitude bits. Negative numbers are represented using**two's complement**notation**places:**this is optional and represents the number of characters to use. If**places**is omitted,**BIN2OCT**uses the minimum number of characters necessary. The argument**places**is useful for padding the return value with leading 0s (zeros).

**Two's complement** is a mathematical operation on binary numbers, as well as a binary signed number representation based on this operation. The two's complement of an **N**-bit number is defined as the complement with respect to 2** ^{N}**; in other words, it is the result of subtracting the number from 2

**. This is also equivalent to taking the ones' complement and then adding one, since the sum of a number and its ones' complement is all 1 bits. The two's complement of a number behaves like the negative of the original number in most arithmetic, and positive and negative numbers can coexist in a natural way.**

^{N}It should be further noted that:

- If
**number**is not a valid binary number, or if**number**contains more than 10 characters (10 bits),**BIN2OCT**returns the*#NUM!*error value - If
**number**is negative,**BIN2OCT**ignores**places**and returns a 10-character octal number - If
**BIN2OCT**requires more than**places**characters, it returns the*#NUM!*error value - If
**places**is not an integer, it is truncated - If
**places**is nonnumeric,**BIN2OCT**returns the*#VALUE!*error value - If
**places**is negative,**BIN2OCT**returns the*#NUM!*error value

Please see my example below:

*We’ll continue our A to Z of Excel Functions soon. Keep checking back – there’s a new blog post every other business day.*