Explain this Excel formula

You inherited a spreadsheet, or you wrote a formula six months ago, and now you can’t remember what it does. Paste the prompt below into ChatGPT, Claude, Microsoft Copilot, or Gemini, then paste the formula under it. You’ll get a plain-English explanation, a simpler version if there is one, and a couple of things to watch for.

This prompt is a starting point. Try it on a formula you already understand and tweak the wording before we treat it as a library staple.

The prompt

Explain this Excel formula like I'm new to Excel.

1. Say in one or two sentences what it returns, in plain English.
2. Walk through the formula left to right and explain each function and range.
3. Call out anything fragile: hard-coded values, volatile functions, or ranges that will break if I insert rows or copy the formula down.
4. If there's a simpler or clearer way to get the same result in modern Excel (including dynamic array functions), show it and explain the tradeoff.
5. Give two examples: one normal case and one edge case (blank cells, text where a number is expected, or a missing match).

Here's the formula:

[paste the formula here]

If it helps, here's a short description of the sheet and the column headers:
[optional context]

How to use it

1. Copy the prompt.
2. Paste your formula where it says [paste the formula here]. Include the leading =.
3. If you can, add one line of context, like “Column B is the unit price, column C is quantity, column D is a discount code.”
4. If the formula refers to other sheets or named ranges, mention those too, or paste a small sample of the data with personal or business details removed.
5. Read the “fragile” section before you change anything in a shared workbook.

A few extras you can add

If the first answer is too vague, send a follow-up:

Rewrite the simpler version and add a comment I can paste above the formula, one line, that explains what it does.

If you use Microsoft 365 and Copilot is already in Excel, you can ask there instead and keep the file closed to the public chat tools. Don’t paste confidential payroll, customer, or health data into a public AI chat.

Need hands-on help?

If the formula is part of a messy workbook you don’t want to break, I can look at it with you over a remote session. Support is after-hours, nationwide, with local help in the Dallas–Fort Worth area. See Work with me.