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ISOMITTED Function
Summary
The ISOMITTED function determines if a parameter passed to a LAMBDA function is missing or omitted. It returns TRUE when no value is provided for the argument, enabling flexible lambda functions that can handle variable numbers of parameters gracefully.
Syntax
ISOMITTED(argument)Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
| argument | Any |
Yes | The value or LAMBDA parameter you want to check if it was omitted |
Using the ISOMITTED Function
ISOMITTED is crucial for creating robust LAMBDA functions that can operate with varying numbers of arguments. When building reusable lambda formulas, use ISOMITTED to detect missing parameters and provide default behavior or meaningful feedback.
Common ISOMITTED Examples
Handle Missing Parameter
=LAMBDA(x,y,IF(ISOMITTED(y),"y not provided",x+y))(10,)Returns 'y not provided' when second parameter is omitted
Default Value for Missing Argument
=LAMBDA(x,y,IF(ISOMITTED(y),x*2,x+y))(15,)Doubles x if y is omitted, otherwise adds them
Frequently Asked Questions
Common Errors and Solutions
#VALUE! error
Cause: Using ISOMITTED outside LAMBDA context or with non-parameter values
Solution: Ensure ISOMITTED tests actual LAMBDA parameters only
Unexpected FALSE result
Cause: Argument passed as empty string instead of omitted
Solution: Omit the argument completely rather than passing empty values
Notes
- Available only in Excel 365 and Excel 2021
- Works specifically with LAMBDA function parameters
- Does not detect blank cells or empty strings - only true omissions
- Combine with IF for default parameter values
Compatibility
Available in: Excel 365, Excel 2021
Not available in: Excel 2019, Excel 2016, Excel 2013, Excel 2010, Excel 2007, Excel 2003
Content last reviewed: December 9, 2025
Update frequency: As needed
Excel versions tested: Excel 365, Excel 2021