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Data Hygiene

How to Use IS Data Validation Functions

Last updated: 2026-09-06

⚡ Quick Answer

IS data functions evaluate cell contents and return TRUE or FALSE based on data type rules.

=ISNUMBER(A2)

📊 Visual Demo

Book1 - Excel
HOME · INSERT · FORMULAS · DATA
fx =ISNUMBER(A2)
ABCDE
11450.00Is Number?=ISNUMBER(A2)TRUE
22Text StringIs Text?=ISTEXT(B2)TRUE
33Empty CellIs Blank?=ISBLANK(C2)TRUE

🧠 Deep Dive

IS data functions evaluate cell contents and return TRUE or FALSE based on data type rules.

Key Insights

  • Import problems are often hidden non-breaking spaces.
  • Numbers stored as text break SUM and lookups.

Common Mistakes

  • Running VLOOKUP against uncleaned keys.
  • Using Find & Replace on spaces blindly.

Pro Tips

  • Add a helper column with LEN().
  • Standardize case with UPPER.

FAQ

What does this formula do in plain English?

IS data functions evaluate cell contents and return TRUE or FALSE based on data type rules.

Why is my formula not working?

Running VLOOKUP against uncleaned keys.

Does this work in Google Sheets?

Yes, this syntax is fully compatible with Google Sheets.

What is the most common mistake?

Using Find & Replace on spaces blindly.

Related Guides

How to Use the UNIQUE Function in ExcelHow to Remove Extra Spaces in ExcelHow to Split Text in ExcelHow to Highlight Duplicates in ExcelExcel Error Hub

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