This is part 4 in my series on AI ROI.
- Part 1 was about turning hours saved into real results here
- Part 2 was about getting the same results with less AI usage here
- Part 3 was about which ideas deserve your budget here
Today it is about the ROI hiding in a tool you already open every day.
Several days every week, lost to Excel clean-up
My team used to waste days every single week inside Excel, just cleaning files.
Like corporate card statements with 30 tabs, one per cardholder, with columns only the bank needs.
Someone has to merge it, trim it, check it and make it look good for the boss. This one file alone takes a whole afternoon. Sound familiar?
Usually that someone is your best analyst. So what happens on their day off?
Somebody else opens the file. The afternoon starts again.
Here’s what I do now. I taught Copilot in Excel how to do the job, and saved it as a skill. Today I type two words, and get the clean file, the audit tab and the branded dashboard.
So let me show you the ROI that’s already inside Excel. One skill, that you build one time, that you then run an unlimited amount of times with just 2 words.
Copilot in Excel Skills
When people ask me “What is the best AI tool” I always say this: It’s the tool that the team actually use, and the tool where you use all of the capability. Which means:
A) You get better ROI because the team use it instead of ignore it
B) You find additional use cases to prove your ROI that you did not realize existed
Today, we are talking about Copilot Skills in Excel. But in Copilot you also have:
- Copilot Chat – That you can use as a thought partner when analyzing data, presenting, making financial decisions etc
- Copilot Cowork – That you can use to carry out finance tasks (like reconciliation) automatically
- Copilot in Word, PowerPoint, Outlook, Teams etc – That you can use to improve the quality of your work across office applications.
Each one of these capabilities will produce ROI by itself, but a lot of people will only use 10-20% of the capability of the tool because they don’t even look!
Back to Skills.
A Copilot skill is a set of instructions for one Excel job, saved as a file. Basically, it’s a long prompt you write once. It sits in your OneDrive as a small text file, and you run it by typing @ and its name inside Copilot in Excel.
Two things make it better than a normal prompt. You never retype it. And since it’s a file, you can share it with your team, or use it in other tools, not only in Copilot in Excel.
In my last newsletter on ROI, I said ideas have no ROI, but actionable blocks do.
A skill is one of those blocks, and it’s already in the tool your team already opens every day.
Plus, Microsoft is also rolling skills out to Copilot Chat from this month so you will be able to use them everywhere you use Copilot.
Today you’ll build a few of your own.
I call the routine ‘The Skill Chain’. Six steps: Show it, Write it, Park it, Check it, Brand it, Chain it.
My example is the card statement file. But you can swap in any job your team repeats every month.
The Skill Chain Method
Step 1: Show it. Do the job once in Copilot, and check the result.
Don't write the skill first. How would you even describe a whole Excel job to AI? So do the job once in Copilot, in plain words. That way you know Copilot can do it, and you can check the result.
This is the prompt I used on the card statement file:
I want to consolidate all the tabs into one tab and I want to keep only the date, the description, the amount and the chargebacks. Also tell me for each line from which company and which cardholder it corresponds to. Also structure each cardholders' transactions by date. Use formulas, don't hardcode anything.
A few minutes later:
- Empty rows gone
- Bank-only columns dropped
- One clean tab with the company and cardholder on every line
Tip – Stay in the same chat. In the next step you'll say "this workflow", so Copilot needs the whole job still in view.
Step 2: Write it.
Happy with the result? Then make it repeatable. In the same chat, ask Copilot to write the skill for you:
Write me a skill file as text for this workflow that I can upload to the onedrive skills folder and later reuse here. Skill name: data-cleaning. Make sure to capture every detail of the workflow inside as instructions.
It is a plain text file with specific formatting that makes it easier for AI to understand.
The last is important. It's what tells AI to be detailed.
Excel can't save the file into your skills folder by itself yet. So there's one small manual bit.
- Copy the text Copilot gives you.
- Open a normal Copilot chat and paste it.
- Ask Copilot to turn it into a markdown file.
- Download the .md file.
Step 3: Park it.
Put the file in the right folder, with the right names. This part sounds technical. It isn’t. It’s a few clicks.
- In Copilot in Excel, click the three dots at the top.
- Click Manage plugins & skills, then Custom skills.
- Click Create OneDrive folder, then Open skills folder.
- Create a folder named after your skill. Mine is data-cleaning.
- Upload your .md file into that folder and rename it SKILL.md.
Get either name wrong and the skill won’t work.
From now on, when a new card statement comes in, type @ and the skill name, like @data-cleaning. It cleans the file the same way each time.
Step 4: Check it.
Here's the limit. You can't trust the clean data 100% yet. It's a lot of data, and AI makes mistakes, like humans do. So you need a check.
Here's the next prompt:
Create an audit tab and verify the consolidated data against the sources using formulas, ensuring accuracy, correct formatting, and unchanged originals. Fix and recheck failures before completion, explaining any remaining exceptions.
I always want an audit step in my process, so it gets a skill of its own:
- Reuse the Step 2 prompt. Only the name changes: audit-card.
- Park it in its own folder, like in Step 3.
Tip – If Copilot hardcodes a number, you can't see where it came from. With formulas, you click any cell and trace it back to the source. Much easier to check, no?
Step 5: Brand it.
Even clean and audited, this file is a big table of numbers nobody wants to look at in a management meeting. So we need a dashboard.
First, write the branding skill.
This is the small skill that impresses people the most when I show it live. You define your visual rules once. After that, every dashboard, KPI card and chart comes out in your company's colors and fonts, without you asking again.
I wrote it with my CSI framework: Context, Specific, Instructions. Who I am, then the detail of the colors, the number formats and where the KPIs go.
Write me a detailed skill as text named finance-branding. Use it whenever creating or restyling any dashboard, KPI report, chart or summary sheet in Excel. I am a CFO. White clean base with dark blue highlights for trends and key numbers. Big titles, big numbers. Horizontal KPI cards at the top with a trend indicator. Semantic colors, green for favourable and red for unfavourable. Highlight a variance only when it is material, above 5 percent. Thousands separator, no decimals on amounts, percentages with one decimal. Always add a short narrative under the charts. Drill-down over clutter.
Swap "I am a CFO" for your own role, and the colors for your own.
Park it like in Step 3, in a folder called finance-branding.
Then, ask for the dashboard.
Look how short this prompt is:
From the consolidated tab, build a dashboard for analysis in the new tab. Do not hardcode anything, use formulas.
It's short because the branding skill carries the look. I never mentioned it. Copilot found it by itself.
Last, save the dashboard as a skill.
Write a skill.md instructions based on the workflow. Make sure to get every detail inside.
Park it in its own folder, called cost-dashboard.
Step 6: Chain it.
You now have separate skills. Next comes one skill that calls them in order.
I do it this way on purpose. I want to see at which step a mistake appears, and step in if I need to. So the last line makes Copilot stop and wait for my approval after each step.
Write a skill.md instructions as text named card-cycle.
When I call card-cycle the following needs to be done:
Step 1: invoke the data-cleaning skill.
Step 2: invoke audit skill to audit the consolidation.
Step 3: invoke the cost-dashboard skill which will use the tabs created from data-cleaning and audit.
After each step, stop and wait for my approval.
Then I opened a brand new card statement file, opened Copilot and typed @card-cycle.
- Step one: 1,005 transactions consolidated from 30 source tabs. I approved.
- Step two: the audit ran, everything passed and the totals matched. I approved again.
- Step three: the branded dashboard.
And boom. The clean file, the audit tab and the branded dashboard. From two words I typed.
Those approval stops are the point. AI prepares the work. You decide what moves to the next step.
Now the ROI part. I could say “a full day saved” and stop. But we started this ROI series with why ‘hours saved’ is the wrong metric. I told you it’s the laziest way to count. Because an hour saved that is not used for more valuable work is an hour that there was no point in saving.
So, when you’re going through this process, first decide where your time will go once freed, or what work you would normally pay for that you don’t have to do any more (e.g subcontract work).
Either way, Skills have high ROI capabilities as they can replace small painful tasks that add up to big headaches for you.
Tasks that you can train AI to carry out consistently and accurately, and chain together for big results.
The One Thing to Remember
A Skill is a small task you never have to do manually again.
And chaining multiple skills together will add up to big returns in time you can use for your more ambitious projects.
And don’t forget. A Skill is only one capability that exists in your AI tool.
Become an expert on an entire tool suite, and your ROI justification will become so much easier 😉
Best,
Your AI Finance Expert,
– Nicolas
P.S. – The best way to learn from me directly is to join my weekly masterclasses. 60-mins + Q&A where I'll get all your AI in Finance questions answered. Join me here.
P.P.S. – Want to see the card-cycle skill built live? Here’s the full walkthrough → How To Build Copilot Skills in Excel Like a PRO in 2026
