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ISNUMBER.

Checks whether a value is numeric and returns TRUE or FALSE.

SyntaxArgumentsExampleInteractive SandboxGeneratorCompatibilityFAQRelatedCheat Sheet
Category: Information
ExcelExcel 365Excel 2021Excel 2019Google Sheets

How it works.

ISNUMBER tests whether a cell or formula result is a valid number. Because Excel stores calendar dates and clock times as numeric serial numbers, ISNUMBER also returns TRUE for valid dates.

Formula syntax.

Standard Excel Notation
=ISNUMBER(value)
Tip:Arguments wrapped in square brackets [like_this] are optional; all other arguments are required.

Formula arguments.

Every parameter accepted by the ISNUMBER function is detailed below.

valueRequired

The cell or expression to test.

Example value: A2

Simple example.

Step-by-Step Scenario

Data Validation - Numeric Price Check

Check if entered price values are numbers or accidental text strings.

ProductPrice InputIs Number?
Monitor249.99—
KeyboardFree—
Mouse29.95—
Applied Formula
=ISNUMBER(B2)
Expected Result:true

Evaluates ISNUMBER over the sample table cells, placing the verified output in cell C2.

Formula generator.

Full Generator Wizard

Customize the argument fields below to generate a tailored ISNUMBER formula ready to paste directly into your worksheet.

Generated FormulaReady to copy
=ISNUMBER()

Expected result behavior.

Returns boolean TRUE based on sample evaluation criteria and active cell references.

Sample Output:true
Output Type:Boolean Flag

Best Practices

  • Nest inside FIND or SEARCH to test if text contains a specific substring: =ISNUMBER(SEARCH("corp", A2)).
  • Dates and times always evaluate to TRUE in ISNUMBER.

Common Mistakes

  • Numbers imported from databases formatted as text strings (e.g. "1200") return FALSE. Use VALUE(A2) to convert them first.
Compatibility Database

Platform & version compatibility.

Verified platform compatibility matrix based on actual spreadsheet calculation engine specifications.

Excel✓
Supported
Excel 365✓
Supported
Excel 2021✓
Supported
Excel 2019✓
Supported
Google Sheets✓
Supported
Microsoft Excel History & Version Availability

Core standard function supported across all modern and legacy Microsoft Excel versions (365, 2021, 2019, 2016, 2013, 2010), as well as Excel for the Web and Mac.

Google Sheets Compatibility Notes

100% compatible with Google Sheets. Uses identical argument order, data types, and standard calculation logic.

Frequently asked questions.

Technical Q&A
Can I use ISNUMBER across different worksheets in Excel?↓

Yes. You can reference cells located on other sheets by including the sheet name followed by an exclamation mark, for example: =ISNUMBER(Sheet2!A2:A10). If the sheet name contains spaces, enclose it in single quotes: ='Q1 Report'!A2:A10.

What is the most common reason for errors in ISNUMBER?↓

Numbers imported from databases formatted as text strings (e.g. "1200") return FALSE. Use VALUE(A2) to convert them first.

Does ISNUMBER work identically in Google Sheets?↓

Yes, ISNUMBER is supported in both Microsoft Excel and Google Sheets with standard evaluation behavior.