Excel BIN2DEC Function will convert from a binary number and return to its decimal equivalent. This article will show you exactly how to use BIN2DEC Function


The syntax for Excel BIN2DEC function is:

=BIN2DEC (number)


  • “number” is the binary number to be converted to decimal


The BIN2DEC is a built-in function in Excel that receives a binary number and returns the corresponding decimal value. Any input value must have only 0’s and 1’s and also must not be more than 10 characters (10 bits) in length. Otherwise, the function will return an “#NUM!” error.


In figure 1 below, the formula in C7 is:


And it returns 25.

The -2 value in cell C9 is represented by two complement notation

Figure 1. Use Excel BIN2DEC function

Usage Notes 

  • The binary number first digit shows whether the integer is negative or positive, while the remaining nine are integer size with a maximum of 511. That is, (2^9 – 1).
  • A binary number that is negative will likely be represented by two (2) complement notation
  • This function is available in Excel 2007 and later versions.
  • The length of the input number must be under 10 characters, and also contain only zeros and ones.