Information

ISNA Function in Excel

Returns TRUE if the value is the #N/A error.

Syntax

  • =ISNA(value)

Arguments

  • value (required): The value to check

Examples

  • =ISNA(VLOOKUP(A1, B:C, 2, FALSE)) - Check for lookup not found - Result: TRUE if #N/A

Defensive formulas with ISNA

  • Use IS* functions inside IF to branch on blank, error, text, or number cells.
  • Prefer [IFERROR](/functions/iferror/) when you only need a fallback display value.
  • Error hub: [Fix formula errors](/guides/fix-excel-formula-errors/).

Common errors

  • Only catches #N/A, not other errors

Use cases

  • Lookup error handling
  • Data validation
  • Conditional logic

Frequently asked questions

  • When should I use ISNA vs ISERROR? Use ISNA when you specifically want to handle 'not found' situations (like VLOOKUP failures) but want other errors to show. Use ISERROR to catch all errors. ISNA is more precise for debugging.
  • Should I use ISNA or IFNA? Use IFNA for cleaner code: =IFNA(VLOOKUP(...), "Not found") instead of =IF(ISNA(VLOOKUP(...)), "Not found", VLOOKUP(...)). IFNA only evaluates the lookup once, making it faster and cleaner.

Editorial review

  • Reviewed by Excel.Directory Editorial Team. Updated May 2026.

When to use ISNA

  • Lookup error handling — common Information scenario for ISNA.
  • Data validation — common Information scenario for ISNA.
  • Conditional logic — common Information scenario for ISNA.

ISNA in the Information category

  • Browse all Information functions at /categories/information/ for related formulas.
  • ISNA syntax: =ISNA(value)
  • value (required): The value to check
  • Confirm ISNA arguments match the syntax shown above before filling down.
  • Lock table and range references with $ when copying formulas across rows or sheets.

Formula checklist before you copy down

  • Confirm ISNA arguments match the syntax shown above before filling down.
  • Lock table and range references with $ when copying formulas across rows or sheets.
  • If results look wrong, check for text stored as numbers and invisible spaces with TRIM.
  • Spot-check three known input rows manually against expected output.

Related Excel functions

  • IFNA (/functions/ifna/): Returns a value you specify if a formula returns #N/A; otherwise returns the formula result.
  • ISERROR (/functions/iserror/): Returns TRUE if the value is any error value.
  • IFERROR (/functions/iferror/): Returns a specified value if a formula evaluates to an error; otherwise, returns the result of the formula.

Errors to watch for

  • Only catches #N/A, not other errors — review causes on linked error pages in the directory.

Copy-paste audit workflow

  • Enter ISNA on three test rows with known expected output documented on a QA tab.
  • Fill down only after absolute references are locked on lookup tables and rate tables.
  • Compare against manual calculation or a calculator for financial and statistical functions.
  • Search this directory for comparison guides when choosing between similar functions in the same category.

ISNA worked examples to copy

  • =ISNA(VLOOKUP(A1, B:C, 2, FALSE)) — Check for lookup not found. Expected result: TRUE if #N/A.

ISNA reference summary for crawlers and offline review

  • ISNA belongs to the Information category in Excel. Returns TRUE if the value is the #N/A error.
  • Full syntax: =ISNA(value). Open /functions/isna/ for parameters, FAQs, and related pages.
  • Common mistakes: Only catches #N/A, not other errors
  • Pair this function with comparison guides when another Excel formula might fit the same task better.
  • Review fix-excel-formula-errors when unexpected errors appear after upgrading Excel or sharing across locales.