ISFORMULA Function in Excel
The ISFORMULA function checks if a cell contains a formula and returns TRUE or FALSE. Learn syntax, examples, and common use cases for Excel formula auditing.
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Google SheetsExcel=ISFORMULA(reference)Quick Answer
ISFORMULA function ISFORMULA function checks whether a cell contains a formula and returns TRUE or FALSE. Use `=ISFORMULA(reference)` where reference is the cell to test. Available in Excel 2013+, it's essential for formula auditing, data validation, and spreadsheet quality control.
=ISFORMULA(reference)Practical Examples
Basic Formula Detection
Check if a cell contains a formula
Formula Audit Report
Create a validation column to identify formula cells
Conditional Formatting Rule
Highlight all formula cells with background color
Count Formula Cells in Range
Count how many cells in a range contain formulas
Protect Formula Cells Only
Identify formula cells for selective sheet protection
Common Errors and Solutions
ISFORMULA returns #VALUE! error
The reference argument is not a valid data type. This typically occurs when using a defined name that doesn't reference a cell, or when the reference is a constant value rather than a cell reference.
1. Verify your reference is a valid cell address (e.g., A1, not "A1") 2. Check that named ranges actually reference cells 3. Ensure you're not passing a constant value directly 4. Use proper cell reference format without quotes
Always use direct cell references like A1 or named ranges that point to actual cells. Test your reference by clicking on it in the formula bar to verify it highlights cells.
Example:
ISFORMULA returns FALSE when cell visually contains a formula
The cell may contain text that looks like a formula (e.g., starts with =) but is stored as text format, often due to preceding apostrophe or text formatting applied before formula entry.
1. Check if the cell has an apostrophe prefix (visible in formula bar) 2. Verify cell format is not set to Text 3. Re-enter the formula in a General or Number formatted cell 4. Use Formula > Show Formulas to verify true formulas
Format cells as General before entering formulas. Avoid pasting formulas as text. Check the formula bar to ensure no apostrophe appears before the equals sign.
Example:
Slow calculation when ISFORMULA used in large ranges
Using ISFORMULA in array formulas or with volatile functions across thousands of cells can slow workbook calculation, especially when combined with SUMPRODUCT or other array operations.
1. Limit the range to only necessary cells 2. Use Table references for dynamic ranges 3. Consider VBA for large-scale auditing 4. Break large ranges into smaller segments 5. Calculate manually (Formulas > Calculation Options > Manual)
Use ISFORMULA strategically in smaller ranges or one-time audits rather than live formulas across entire sheets. For permanent solutions, consider converting to values after audit.
Best Practices and Pro Tips
Conditional Formatting for Visual Audit
Combine ISFORMULA with conditional formatting to instantly visualize all formula cells in your worksheet. Select your data range, apply a conditional formatting rule using =ISFORMULA(A1), and choose a distinct background color. This creates an immediate visual map of your worksheet's calculation structure.
Data Validation Integration
Use ISFORMULA in data validation rules to prevent users from overwriting formula cells. Create a custom validation rule that shows an error when someone tries to enter data in a cell that should contain a formula, protecting your worksheet logic from accidental modifications.
Circular Reference Risk
Be cautious when using ISFORMULA to reference the same cell indirectly. While ISFORMULA itself doesn't create circular references, complex nested formulas using ISFORMULA can inadvertently reference their own cell through intermediate calculations, leading to calculation errors.
Documentation Workflow
Create a dedicated audit worksheet that uses ISFORMULA to document all formulas in your workbook. Use a formula like =IF(ISFORMULA(Sheet1!A1), FORMULATEXT(Sheet1!A1), "") to extract and document formula logic. This serves as automatic documentation for complex workbooks.
Array Formula Compatibility
ISFORMULA works seamlessly with dynamic array formulas in Excel 365/2021. You can use =ISFORMULA(A1#) to check if a spilled array formula exists. This is particularly useful for validating that array formulas are functioning correctly after workbook changes or updates.
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Example Excel formula:
Related Formulas
The FORMULATEXT function displays the formula stored in a cell as text. Learn syntax, practical examples, and solutions to common errors in Excel 2013+.
Excel