Microsoft has put an AI assistant inside Excel, and the marketing suggests you’ll never write a formula again. The tutorials on the other side suggest it’s a gimmick. Both are wrong in useful ways.
I’ve been using Copilot the way I’d assess any new hire: give it real work, check everything, notice patterns. Here’s the honest report. (Requirements note: Copilot needs a Microsoft 365 subscription with the Copilot add-on, and your data in OneDrive/SharePoint with AutoSave on — a real barrier for plenty of workplaces. Everything else on this site works in ordinary Excel; this guide is the exception, filed accordingly under Field notes.)
Where it genuinely earns its seat
- Explaining formulas you inherited. Point it at
=INDEX(A:A,MATCH(1,(B:B=F1)*(C:C=G1),0))and ask “explain this”. Copilot’s plain-English read is fast and usually right — the single best use for anyone maintaining someone else’s workbook. - First drafts of formulas you can describe. “Flag rows where Amount is 20% above the average for that Region” produces a workable draft in seconds. You review it — always — but it types faster than you.
- Bulk grunt work with clear instructions. “Add a column extracting the domain from the email address”, “convert these headers to Proper Case”. The kind of thing you can do, but which eats ten minutes you’d rather keep.
- Suggesting angles on clean data. Given a well-structured Table, “what stands out?” returns two or three chart-plus-sentence starting points. Occasionally one is genuinely worth keeping.
Where it lets you down
- Messy data. Merged cells, headers mid-sheet, totals mixed into the rows — Copilot flounders on exactly the files that fill real inboxes. The 4:45pm cleaning routine isn’t optional because the AI arrived; it’s the prerequisite for the AI being useful at all.
- Your numbers and your judgement. It will confidently summarise; it will occasionally confidently miscount. Anything that feeds a decision — a report, a price, a pension figure — gets verified by a human with a SUMIFS. No exceptions.
- Knowing what to ask. Copilot answers questions; it doesn’t know that the interesting question about your spend data is the Future ÷ In ratio. Domain sense — the thing the path actually teaches — stays your job.
The habit that makes it safe
One rule covers everything: treat Copilot like a bright temp on their first day. Delegate drafts, never sign-off. Concretely: let it write the formula, then read the formula like you’d read any inherited one — where does it think it’s pointing? If you can’t read the draft, don’t ship the draft; that’s not an AI rule, it’s the same rule this site applies to everything.
| Delegate freely | Keep on your desk |
|---|---|
| Explaining inherited formulas | Verifying any number that matters |
| Formula and column drafts | Choosing the question |
| Formatting grunt work | Cleaning messy source data |
| “What stands out?” starters | The final read before it ships |
The quiet takeaway
Six months of use, one conclusion: Copilot rewards exactly the skills it was supposed to replace. Clean Tables, precise column names, knowing what a right answer roughly looks like — people with those habits get compounding value from AI; people without them get confident nonsense faster than ever.
Which is convenient, because those habits are learnable, in order, for free: that’s the path. The robot is real and it is useful — as an amplifier. Something worth amplifying is still on you.