# The Excel BIN2DEC Function

Binary

The Binary (Base 2) Numeral System uses the digits 0 & 1.

The following table shows the first 8 binary values, along with the equivalent decimal values:

 Binary 1 10 11 100 101 110 111 1000 Decimal 1 2 3 4 5 6 7 8

For further information on the binary numeral system, see the Wikipedia Binary Page

Related Function:
Dec2Bin Function

## Function Description

The Excel Bin2Dec function converts a Binary (a base-2 number) into a decimal number.

The syntax of the function is:

BIN2DEC( number )

Where the number argument is the binary number that is to be converted to a 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.

## Bin2Dec Function Examples

The following spreadsheets show five examples of the Excel Bin2Dec function.

Formulas:
A
1=BIN2DEC( "10" )
2=BIN2DEC( "11" )
3=BIN2DEC( "0000000010" )
4=BIN2DEC( "1111111110" )
5=BIN2DEC( "110" )
Results:
AB
12  Result is   1*2 + 0
23  Result is   1*2 + 1
32  Result is   1*2
4-2  Result is   -2^9 + 2^8 + 2^7 + ... + 2 + 0
56  Result is   2^2 + 2 + 0

Note that, in the above example spreadsheet, the negative binary number in cell A4 is represented by two's complement notation.

Further details and examples of the Excel Bin2Dec function are provided on the Microsoft Office website.

## Bin2Dec Function Error

If you get an error from the Excel Bin2Dec function this is likely to be the #NUM! error:

Common Error
 #NUM! - Occurs if the supplied number argument is not recognised as a binary number, or contains more than 10 characters.