Cellwise

Cleanup function

Excel ISNUMBER function

ISNUMBER returns TRUE if a value is a number and FALSE for anything else. Use it to catch numbers stored as text, guard a calculation, or turn SEARCH into a simple "does this cell contain" test.

fx=ISNUMBER(value)

Arguments

value
The cell or value to test.

ISNUMBER examples

Every result below was calculated live from this sample sheet.

ABCD
1SKUProductIn stockReorder at
2CB-100USB-C cable4220
3CB-101HDMI cable1510
4AD-200Wall adapterTBC15
5AD-201Car adapter812
  1. fx=ISNUMBER(C2)

    Result: TRUE

    TRUE, because 42 is a real number.

  2. fx=ISNUMBER(C3)

    Result: FALSE

    FALSE. The 15 was imported as text, so totals will skip it.

  3. fx=IF(ISNUMBER(C5),IF(C5<D5,"Reorder","OK"),"Check count")

    Result: Reorder

    Only compares stock levels when the count is a real number.

  4. fx=ISNUMBER(SEARCH("cable",B3))

    Result: TRUE

    TRUE when the product name contains "cable" anywhere.

How to use ISNUMBER

  1. Click the cell for the result.
  2. Type =ISNUMBER( and click the cell to test.
  3. Press Enter to see TRUE or FALSE.
  4. Wrap it in IF or use it in conditional formatting.

Common ISNUMBER mistakes

Numbers stored as text

They look like numbers but ISNUMBER says FALSE. Convert them with VALUE or Text to Columns.

Forgetting that dates are numbers

A real date returns TRUE, because Excel stores dates as serial numbers.

Using FIND or SEARCH alone to test for text

They return #VALUE! when nothing is found. Wrap them in ISNUMBER for a clean TRUE or FALSE.

ISNUMBER FAQ

How do I check if a cell contains specific text in Excel?

Use =ISNUMBER(SEARCH("text",A2)). SEARCH returns a position number when it finds the text, so ISNUMBER turns that into TRUE.

Why does ISNUMBER return FALSE for a number?

The number is stored as text, often from an import. Look for a green triangle in the cell corner and convert it to a number.

Does ISNUMBER return TRUE for dates?

Yes. Excel dates are numbers underneath, so a real date gives TRUE. A date typed as text gives FALSE.

Practice ISNUMBER in these lessons

Guides that use ISNUMBER

Related functions

Updated 2026-10-31