Common questions about ISNA usually involve formula errors, parameter entry, result meanings, and nested formula behavior. This FAQ includes 4 common questions and a glossary.
FAQ
What should I do if ISNA shows an error after I enter it?
- Check whether the formula starts with
=. - Make sure the parentheses are paired correctly and the parameter is in the right position.
- Confirm that you entered a valid cell reference, constant, or formula result.
- If a syntax prompt appears, re-enter the formula based on that prompt and press Enter again.
How can I view the ISNA function description?
- Select any cell.
- Enter
=ISNA(in the formula bar. - Review the syntax prompt and parameter guidance that appears.
- Complete the parameter and test the result.
What do TRUE and FALSE mean in ISNA?
- ISNA returns TRUE when the tested value is the
#N/Aerror. - ISNA returns FALSE when the tested value is not the
#N/Aerror. - If you want a more readable result, combine ISNA with IF.
Why does my nested ISNA formula not return the expected result?
- Test the ISNA part by itself in a separate cell first.
- Then check whether the outer IF or other function uses the correct logic branch.
- Confirm that the referenced cell is not entered as text by mistake and that the reference range is correct.
- After data changes, review whether the result updates as expected.
Glossary
| Term | Definition |
|---|---|
| ISNA | A function that checks whether a value is the #N/A error and returns TRUE or FALSE. |
#N/A | An error type that indicates a value is not available or was not found, often after a lookup. |
| Nested formula | A formula structure that uses one function inside another to handle more complex logic or calculations. |
| Cross-sheet reference | A reference that uses a cell from another worksheet in the current formula. |