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10 Common Excel Formula Mistakes and How to Fix Them

January 1, 2026 • 6 min read • Excel, LibreOffice Calc, Google Sheets

Excel formula errors are frustrating, but most are easy to fix once you know what to look for. Here are the 10 most common mistakes and how to fix them.

1. #N/A Error in VLOOKUP

Problem: VLOOKUP can't find the lookup value.

Common Causes:

Lookup value doesn't exist in the table
Extra spaces in the data
Data type mismatch (text vs number)

Fix: Use TRIM to remove spaces, ensure data types match, or use IFERROR to handle missing values:

=IFERROR(VLOOKUP(A1, B:C, 2, FALSE), "Not Found")

2. #VALUE! Error

Problem: Wrong data type used in formula.

Fix: Ensure you're using numbers for calculations, not text. Convert text to numbers:

=VALUE(A1) + B1

3. #REF! Error

Problem: Reference to a cell that no longer exists (deleted row/column).

Fix: Update the formula to reference the correct cells, or use named ranges to avoid this issue.

4. Forgetting Absolute References ($)

Problem: Formula breaks when copied to other cells.

Fix: Use $ to lock cell references:

=VLOOKUP(A1, $B$2:$C$10, 2, FALSE)

5. Missing Parentheses

Problem: Formula doesn't calculate correctly due to order of operations.

Fix: Add parentheses to group operations:

=(A1+B1)*C1  // Correct
=A1+B1*C1    // Wrong (multiplies first)

6. Using Text Instead of Numbers

Problem: Numbers stored as text cause calculation errors.

Fix: Convert text to numbers or ensure cells are formatted as numbers.

7. Wrong Range in SUM/AVERAGE

Problem: Including header rows or wrong cells in calculations.

Fix: Double-check your range references:

=SUM(A2:A100)  // Excludes header in A1

8. Circular Reference

Problem: Formula references its own cell, causing infinite loop.

Fix: Remove the circular reference. Excel will warn you about this.

9. Forgetting FALSE in VLOOKUP

Problem: VLOOKUP returns approximate match instead of exact match.

Fix: Always use FALSE or 0 for exact matches:

=VLOOKUP(A1, B:C, 2, FALSE)

10. Incorrect Column Index Number

Problem: VLOOKUP returns value from wrong column.

Fix: Remember: column index starts at 1, not 0. First column is 1, second is 2, etc.

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Conclusion

Most Excel formula errors are preventable. Pay attention to data types, use absolute references when needed, and always test your formulas with different values. When in doubt, use ExcelFormula Pro to generate accurate formulas automatically!