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DEC2BIN Function
Summary
The Excel DEC2BIN function converts decimal integers to their binary representation. It handles both positive numbers (0 to 511) and negative numbers (-512 to -1) using two's complement notation for negatives.
Syntax
DEC2BIN(number, [places])Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
| number | Number |
Yes | The decimal integer you want to convert to binary. Range: -512 to 511. |
| places | Number |
No | Optional. Number of characters to use in the binary result. Pads with leading zeros if needed. |
Using the DEC2BIN Function
DEC2BIN is perfect for converting decimal values to binary format, especially useful in computer science education, digital electronics, programming, and when working with binary data in spreadsheets. Use it to visualize bit patterns or perform binary calculations.
Common DEC2BIN Examples
Convert Positive Decimal to Binary
=DEC2BIN(9, 4)Converts 9 to 4-digit binary: 1001
Convert Negative Decimal
=DEC2BIN(-100)Converts -100 to 10-bit two's complement binary: 1110011100
Automatic Length Binary
=DEC2BIN(255)Converts 255 to shortest binary: 11111111
Frequently Asked Questions
Common Errors and Solutions
#NUM!
Cause: Number outside range (-512 to 511)
Solution: Use value between -512 and 511
#NUM!
Cause: Result needs more characters than places allows
Solution: Increase places or omit it
#VALUE!
Cause: Non-numeric input
Solution: Ensure number and places are numeric
#NUM!
Cause: Places is zero or negative
Solution: Use positive integer for places
Notes
- Maximum 10-bit output for negative numbers
- Places parameter truncates non-integer values
- Omit places for minimum length binary
- Two's complement for negative numbers
Compatibility
Available in: Excel 2007, Excel 2010, Excel 2013, Excel 2016, Excel 2019, Excel 365
Not available in: Excel 2003 and earlier
Content last reviewed: December 9, 2025
Update frequency: As needed
Excel versions tested: Excel 2007+, Excel 2010, Excel 2013, Excel 2016, Excel 2019, Excel 365