DEC2BIN function

This article describes the formula syntax and usage of the DEC2BIN function in Microsoft Excel.


Converts a decimal number to binary.


DEC2BIN(number, [places])

The DEC2BIN function syntax has the following arguments:

  • Number    Required. The decimal integer you want to convert. If number is negative, valid place values are ignored and DEC2BIN returns a 10-character (10-bit) binary number in which the most significant bit is the sign bit. The remaining 9 bits are magnitude bits. Negative numbers are represented using two's-complement notation.

  • Places    Optional. The number of characters to use. If places is omitted, DEC2BIN uses the minimum number of characters necessary. Places is useful for padding the return value with leading 0s (zeros).


  • If number < -512 or if number > 511, DEC2BIN returns the #NUM! error value.

  • If number is nonnumeric, DEC2BIN returns the #VALUE! error value.

  • If DEC2BIN requires more than places characters, it returns the #NUM! error value.

  • If places is not an integer, it is truncated.

  • If places is nonnumeric, DEC2BIN returns the #VALUE! error value.

  • If places is zero or negative, DEC2BIN returns the #NUM! error value.


Copy the example data in the following table, and paste it in cell A1 of a new Excel worksheet. For formulas to show results, select them, press F2, and then press Enter. If you need to, you can adjust the column widths to see all the data.




=DEC2BIN(9, 4)

Converts decimal 9 to binary with 4 characters.



Converts decimal -100 to binary


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