This article describes the formula syntax and usage of the DEC2BIN function (function: A prewritten formula that takes a value or values, performs an operation, and returns a value or values. Use functions to simplify and shorten formulas on a worksheet, especially those that perform lengthy or complex calculations.) in Microsoft Excel.
Description
Converts a decimal number to binary.
Syntax
DEC2BIN(number, [places])
The DEC2BIN function syntax has the following arguments (argument: A value that provides information to an action, an event, a method, a property, a function, or a procedure.):
 Number Required. The decimal integer you want to convert. If number is negative, valid place values are ignored and DEC2BIN returns a 10character (10bit) 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'scomplement 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).
Remarks
 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.
Example
The example may be easier to understand if you copy it to a blank worksheet.
How do I copy an example?
 Select the example in this article. If you are copying the example in Excel Online, copy and paste one cell at a time.
Important: Do not select the row or column headers.
Selecting an example from Help
 Press CTRL+C.
 Create a blank workbook or worksheet.
 In the worksheet, select cell A1, and press CTRL+V. If you are working in Excel Online, repeat copying and pasting for each cell in the example.
Important: For the example to work properly, you must paste it into cell A1 of the worksheet.
 To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Formulas tab, in the Formula Auditing group, click the Show Formulas button.
After you copy the example to a blank worksheet, you can adapt it to suit your needs.

A 
B 
Formula 
Description (Result) 
=DEC2BIN(9, 4) 
Converts decimal 9 to binary with 4 characters (1001) 
=DEC2BIN(100) 
Converts decimal 100 to binary (1110011100) 
