Understanding Formula Errors

Last reviewed Jun 1, 2026 Content v20260601

Track mode

none

Means

Read / quiz

Reading

~1 min

Level

beginner

This lesson

This lesson teaches Understanding Formula Errors: Excel concepts, formulas, and analysis patterns you recreate locally in a workbook.

Silent #N/A and #REF! cells ship to executives unless you audit before publish.

You will apply Understanding Formula Errors in contexts like: Finance, operations, reporting, and quick what-if analysis before a full BI stack.

Read the lesson, type formulas in your local Excel or compatible spreadsheet, rebuild examples in excel-practice.xlsx, and complete MCQs—no in-browser runner.

When you can explain the previous lesson's ideas in your own words.

Excel surfaces errors as codes—learn to fix root cause instead of masking with IFERROR blindly.

Codes

`#DIV/0!`	Division by zero
`#N/A`	Lookup not found
`#REF!`	Invalid reference (deleted cells)
`#VALUE!`	Wrong type (text in math)
`#NAME?`	Unknown function name typo

IFERROR

=IFERROR(VLOOKUP(A2,Table,3,FALSE),"Not found")

Audit

Formulas → Trace Precedents/Dependents. Evaluate Formula steps through calculation.

Important interview questions and answers

Q: IFERROR risk?
A: Hides real data problems—log or separate error column in audits.
Q: #N/A?
A: Often lookup mismatch.

Self-check

What causes #DIV/0!?
When is IFERROR dangerous?

Pitfall: Blanket IFERROR on entire columns hides audit trails—use sparingly.

Interview prep

#N/A?: Lookup or match not found.

Discussion

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Starter discussion topics

#N/A meaning?
IFERROR risk?

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