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ISLOGICAL Function

Excel 2007+

Summary

The ISLOGICAL function determines whether a given value is a logical (boolean) value, returning TRUE for TRUE/FALSE values and FALSE for all other data types including text representations of logical values.

Syntax

ISLOGICAL(value)

Parameters

Parameter	Type	Required	Description
value	`Any`	Yes	Value to check - returns TRUE only if it's a genuine logical value

Using the ISLOGICAL Function

ISLOGICAL is perfect for validating data types in spreadsheets, ensuring formulas receive proper boolean inputs, and creating conditional logic based on value types. Use it to filter logical values from mixed data sets or prevent errors in functions expecting boolean arguments.

Common ISLOGICAL Examples

Basic Logical Check

=ISLOGICAL(TRUE)

Tests the TRUE constant - returns TRUE because it's a genuine logical value.

Text vs Logical

=ISLOGICAL("TRUE")

Tests text string "TRUE" - returns FALSE since it's text, not a logical value.

Cell Reference Test

=ISLOGICAL(A1)

Checks if cell A1 contains a logical value. TRUE if A1 has TRUE/FALSE, FALSE otherwise.

Formula Result Check

=ISLOGICAL(AND(B1>10,C1<5))

Tests if AND formula returns logical - always TRUE since AND produces boolean.

Frequently Asked Questions

No, ISLOGICAL("FALSE") returns FALSE because "FALSE" is text, not a logical value.

Only genuine logical values TRUE and FALSE return TRUE. Numbers, text, errors, and blanks return FALSE.

Yes, ISLOGICAL(A1) tests whatever value is in cell A1 and returns TRUE only if it's logical.

Common Errors and Solutions

Always returns FALSE for text

Cause: Testing text strings like "TRUE" instead of actual logical values

Solution: Use actual TRUE/FALSE constants or ensure cells contain logical values

Unexpected results with blanks

Cause: Empty cells return FALSE (not logical)

Solution: Combine with ISBLANK if you need to handle empty cells separately

Notes

ISLOGICAL strictly checks data type - text representations don't qualify
Available since Excel 2007
Part of the IS family of type-checking functions
Does NOT convert values - "1" returns FALSE despite often representing TRUE

Compatibility

Available in: Excel 2007, Excel 2010, Excel 2013, Excel 2016, Excel 2019, Excel 2021, Microsoft 365

Not available in:

Content last reviewed: December 9, 2025
Update frequency: As needed
Excel versions tested: Excel 2007+