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In this article
ISNA returns TRUE only for #N/A — the “not found” result — so you can react to missing lookups specifically.
Syntax
=ISNA(value)| Argument | What it means |
|---|---|
value |
Usually a lookup. |
Examples
Example 1
=IF(ISNA(MATCH(A2, Master!A:A, 0)), "New customer", "Existing")Classify records against a master list.
ISNA in practice
Where you will use it
- Find items missing from another list
- Count unmatched lookups
- Flag new customers
Worked example
TRUE means the code is missing from the master list.
| Code | Formula | Result |
|---|---|---|
| P01 | =ISNA(MATCH(A2,{"P01";"P02"},0)) | FALSE |
| P99 | =ISNA(MATCH(A3,{"P01";"P02"},0)) | TRUE |
| P02 | =ISNA(MATCH(A4,{"P01";"P02"},0)) | FALSE |
Results calculated in Excel.
Mistakes people make
| Mistake | What to do instead |
|---|---|
| Using ISERROR for lookups | ISNA targets only 'not found' |
| Wildcards in codes | Escape * and ? with ~ |
Related functions
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