How to Fix Broken Formulas in Google Sheets with AI (Gemini, 2026)

If you are searching for google sheets ai fix broken formulas, the goal is usually simple: get from #REF! / #VALUE! / wrong outputs to a stable formula you can trust.

This guide focuses on a repeatable workflow using Sheet Agent in Gemini AI for Sheets, not one-off copy-paste fixes.

When this workflow is the right fit

• You already have formulas, but some rows return errors or inconsistent outputs.
• You need to explain why a formula failed before changing production columns.
• You want to test corrected formulas on sample rows before full-column rollout.

Step 1) Isolate one failure pattern first

Before prompting AI, isolate one error pattern per run. This gives clearer fixes.

• Type mismatch: text that should be date/number.
• Range mismatch: lookup array and return array sizes do not align.
• Reference drift: relative references break after fill-down or column moves.

If your issue is setup-level (#NAME?, add-on not initialized, permissions), use Fix formula errors first.

Step 2) Open Sheet Agent and scope only the affected tabs

1. Open Extensions → AI for Sheets → Sheet Agent.
2. Use the Sheet selector to include only tabs that contain the failing formula context.
3. Keep prompts scoped to one formula family at a time.

Scoping tabs helps avoid unrelated context and reduces accidental edits.

Step 3) Use a two-step prompt pattern: diagnose, then correct

Prompt A: diagnose failure cause

Audit this formula in column H and explain why it fails on some rows.
Return:
1) root cause in plain English,
2) which rows are likely affected,
3) one safe correction strategy.

Prompt B: generate corrected formula

Create one corrected Google Sheets formula for H2.
Requirements:
- Handle blanks safely
- Use IFERROR with a clear fallback
- Preserve output type as number
Return formula only.

For formula creation from scratch (instead of troubleshooting), use this dedicated guide: How to Use Google Sheets AI Formula Generator.

Step 4) Validate before full-column rollout

• Edge rows: test blank rows, malformed rows, and outlier values.
• Type check: confirm numeric/date outputs are real typed values.
• Comparison check: compare old vs new outputs on 20–50 sample rows.
• Performance check: verify recalculation speed on realistic row counts.

After validation, if you need stable snapshots for reporting, save final outputs with Save formula output.

Common mistakes (and safer alternatives)

• Mistake: Ask AI to “fix everything” in one prompt. Safer: one formula family per run.
• Mistake: Replace production formula immediately. Safer: test in helper column first.
• Mistake: Ignore source data typing. Safer: normalize dates/numbers before formula fixes.
• Mistake: Treat AI output as final truth. Safer: run sampling + edge-case checks.

FAQ

Can AI fix every formula error automatically?

Not always. AI can speed up diagnosis and draft better formulas, but you still need validation on your sheet data.

Should I debug in Sheet Agent or with cell-by-cell edits?

Use Sheet Agent for faster diagnosis and draft corrections, then validate with cell-level checks before rollout.

What if the corrected formula still fails?

Narrow the scope: isolate one error pattern, provide 3–5 failing examples, and re-run the diagnose prompt with explicit output-type rules.

Next step

Build a small internal troubleshooting prompt library (diagnose template + correction template + validation checklist). It reduces repeated formula failures and shortens cleanup time for future spreadsheets.