ChatGPT for Excel Formulas: Try Them on Fake Rows

Oct 21, 20267 min readBy Siqwes

You know the result you want from a spreadsheet, but the formula takes trial and error. ChatGPT for Excel formulas helps: describe your columns, ask for one formula, and try it on fake rows first, so real client data stays in your firm's approved systems.

Why do spreadsheet formulas take so much trial and error?

A formula has to fit your exact layout: the right tabs, the right columns and the right result. AI writes with the same confidence whether a formula is right or wrong. The most useful requests also come straight from a real client file, which makes it tempting to paste real rows into the chat.

How can ChatGPT help with Excel formulas?

Describe your sheet by its column headers only and say what result you want. The prompt asks ChatGPT for one formula, a plain-words explanation, six rows of fake sample data for each tab and the formula's limits. You paste the fake rows into a blank practice sheet and try the formula there. ChatGPT has a free version.

What are the steps to get a formula from ChatGPT?

Five steps take you from a question to a formula you trust. Your firm's AI rule comes first. The confidentiality rule is simple: the AI sees column headers and fake rows only, while client names, SSNs, account numbers, tax return information, transactions and exports stay in your accounting software and your firm's approved systems.

Check your firm's rule on AI tools.
Write down your tabs and column headers, with real rows kept in your files.
Paste the prompt below into ChatGPT, adjusting the tab and column names.
Paste the fake rows into a blank practice sheet and try the formula there.
Check the results (see below) before you use the formula in a real file.

Like we saw in Day 4 of our free educational series for bookkeepers, you describe your sheet by its column headers only, and let AI build fake rows for testing.

What Excel formula prompt can you copy?

This prompt is written for a matching check between a Bank tab and a Ledger tab. It asks for a formula that shows "Yes" or "Check," fake rows that include a duplicate and an unmatched amount, and the formula's limits. Rename the tabs and columns to fit. It's written for ChatGPT, and Gemini handles it too.

Try it

I'm working in [Excel / Google Sheets]. I have two tabs.
Tab "Bank": columns A Date, B Description, C Amount
Tab "Ledger": columns A Date, B Memo, C Amount, D Matched?

I want a formula in Ledger column D that shows "Yes" if the same amount
appears in Bank column C, and "Check" if it doesn't.
1. Give me the formula and explain each part in plain words.
2. Give me 6 rows of clearly FAKE sample data for each tab to test it,
   including one amount that appears twice and one that doesn't match.
3. Tell me the formula's limits (for example, duplicate amounts).
4. This is a matching helper, not a reconciliation. Don't call it one.

Click or tap the box to select the whole prompt, then copy it.

Why does each part of the formula prompt matter?

Each line of the prompt has one job, and knowing those jobs helps you rename the tabs and columns while keeping what makes the answer useful. The first lines describe your sheet by its headers, the next line names the result, and the four numbered asks shape the answer.

The tab lines. Tab names and column letters give the AI your layout. Headers carry the structure, and the rows stay in your files.
Ask 1, the explanation. A plain-words explanation helps you understand the formula before you rely on it.
Ask 2, the fake rows. One amount that appears twice and one unmatched amount give you rows where you already know the right answer.
Ask 3, the limits. Duplicate amounts are the classic weak spot of a matching formula, so the limits tell you where to look closely.
Ask 4, the name. The last line keeps the label accurate: a matching helper, with the reconciliation itself done in your accounting software and your review.

How can a checklist turn a real question into a safe one?

Sometimes the formula question starts from a real client file, with names and amounts on screen. A second way comes from the same lesson. You work through a checklist in your own document, outside the AI tool, before the request goes anywhere near it.

Try it: step 2

ANONYMIZING CHECKLIST (do this outside the AI tool)
[ ] Client, business, vendor, customer, and staff names → [Client], [Vendor A]
[ ] Exact amounts → made-up round numbers or [amount]
[ ] Dates → [month] or "last month"
[ ] Account, card, routing, invoice, and ID numbers → removed
[ ] SSNs, EINs, TINs, tax return details (anything a client gave you for, or
    that came from, a tax return) → removed
[ ] Location, industry details that narrow it to one client → generalized
[ ] Still identifiable? → don't use AI for this one

Click or tap the box to select the whole prompt, then copy it.

Run the checklist first, then describe what is left by its headers. If the request still points to one client, keep that question inside your firm's approved systems.

What does it look like in practice?

Say a bookkeeper wants to spot ledger amounts missing from the bank tab. The answer should come back with a formula and fake rows. If the fake data leaves out the duplicate amount or the missing Ledger amount, the bookkeeper asks for both in the same chat, then confirms in the practice sheet that the unmatched row shows "Check."

Here is the same routine as a before and after, using placeholders:

Before: a request that describes rows from [Client]'s bank export, with [Vendor A], exact amounts and dates in the text.
After: a request that names Tab "[Tab 1]" and Tab "[Tab 2]", their headers such as [Date header] and [Amount header], and the result you want in [Result column].

The after version carries everything the formula needs, and the client details stay in your firm's approved systems.

What are common snags with AI spreadsheet formulas?

Most snags show up on the fake rows, which is exactly why you try the formula there first. These three fixes cover the snags that come up most often with a matching formula, and each keeps real data in your firm's systems.

If a result looks wrong on one row, try comparing that row with the formula's explanation to find the part that looks in the wrong place.
If the formula points at the wrong column, try changing the column letter in both the tab line and the result line, then ask again in the same chat.
If the duplicate amount behaves differently from the limits, try rereading the limits and keep that note beside the formula.

How do you check the formula?

Try the formula on the fake rows first and compare each result with what you expect by eye. Every matched amount should show "Yes," the unmatched one should show "Check," and the duplicate should behave the way the limits describe. Run this check before the formula goes anywhere near a real file:

Each result on the fake rows is the one you expect.
The duplicate amount behaves as the limits describe.
Results in a real file match your software's own reports.
Real client rows stay in your firm's approved systems.

Where to look first: the column letters, the duplicate amount and the unmatched row. Before you read the results, mark each fake row with the answer you expect, so your marks become an answer key.

What do you get?

You get one formula you've tried on fake rows, a plain-words explanation and a practice sheet to reuse for the next formula. A matching formula is a helper, and your accounting software and review stay the source of truth. For how an item should be recorded or reported, your firm's reviewer or a CPA is the right person to confirm.

What do bookkeepers often ask about AI formulas?

Three questions come up often when bookkeepers start asking AI for formulas. Each short answer keeps the same habit at its center. Headers go in the prompt, fake rows go in a practice sheet, and real client data stays in your firm's approved systems.

Can I use this with a QuickBooks Online or Xero export?

Yes. Describe the export's column headers in the tab lines, then try the formula on fake rows.

Is a matching formula the same as a reconciliation?

A matching formula is a helper. Your accounting software and your review stay the source of truth.

What if the AI gives me a different formula next time?

Try each version on the same fake rows, and save the one that matches your answer key.

What tip helps with your next formula?

Keep the practice sheet. With fake rows for both tabs already in place, it becomes a test bench for the next formula you need. Add a short note at the top with the tab names, the column letters and the limits you found, so each new request starts from the same layout.