ISNUMBER Function

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The Excel ISNUMBER function tests whether a value is a number. It returns TRUE or FALSE, making it the building block of error-proof formulas, validation, and conditional logic.

Quick answer: test a cell:
=ISNUMBER(A2) // TRUE when the value is numeric

Syntax

=ISNUMBER(value)
ArgumentDescription
valueRequiredThe value, cell, or expression to test.

How to use it

ISNUMBER returns TRUE when the value is numeric, and FALSE otherwise. Wrap it in IF to act on the result, or sum it with SUMPRODUCT to count matches: =SUMPRODUCT(--ISNUMBER(A2:A100)).

The IS family: ISBLANK, ISNUMBER, ISTEXT, ISLOGICAL, ISNONTEXT, ISERR, ISERROR, ISNA, ISREF, ISFORMULA, ISEVEN, and ISODD each return TRUE or FALSE so you can branch with IF, count with SUMPRODUCT, or drive conditional formatting.

Try it: interactive demo

Live demo

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Result:

Practice workbook

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Frequently asked questions

How is ISNUMBER used with SEARCH?
The classic “cell contains text” test: =ISNUMBER(SEARCH("abc",A2)) is TRUE when A2 contains "abc".
How do I act on the TRUE/FALSE result?
Wrap it in IF: =IF(ISNUMBER(A2), "yes", "no").
Can I count how many cells pass?
Yes: =SUMPRODUCT(--ISNUMBER(range)) counts the TRUEs.

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Related functions: ISERROR · ISNUMBER · ISBLANK · IFERROR · NA