Syntax
ISNA(value)
| Parameter | Description |
|---|---|
| value | Parameter of the ISNA function. |
Examples
Handle lookup miss
Formula
=IF(ISNA(VLOOKUP(A1, D:E, 2, FALSE)), "New customer", VLOOKUP(A1, D:E, 2, FALSE))
Returns "New customer" when the ID isn't found, but lets other errors (#REF!, #VALUE!) surface so you catch real problems.
Flag unmatched records
Formula
=ISNA(MATCH(A1, B:B, 0))
Returns TRUE if A1 doesn't exist in column B. Useful for finding records in one list that don't appear in another.
Conditional not-found count
Formula
=SUMPRODUCT(ISNA(VLOOKUP(A1:A50, D:E, 2, FALSE))*1)
Counts how many items in A1:A50 are not found in column D. Useful for reconciliation reports.
Common Errors
#VALUE!
ISNA never errors on its own — it always returns TRUE or FALSE, regardless of input.
Tips
ISNA vs ISERROR
ISNA only catches #N/A (lookup failures). ISERROR catches everything. Use ISNA when you expect lookup misses but want other errors to alert you.
IFNA is cleaner
Instead of IF(ISNA(expr), fallback, expr), use =IFNA(expr, fallback). Evaluates the expression only once.
Lookup reconciliation
Use =ISNA(MATCH(A1, other_list, 0)) to find items that exist in one list but not another. Filter by TRUE to see all unmatched records.
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