Asking a language model questions about your own spreadsheet

Two different things people mean by this

When someone says they’re doing ai spreadsheet analysis, they usually mean one of two different setups, and they behave very differently.

The first is pasting a chunk of your spreadsheet, or a summary of it, into a chat window and asking questions in plain English. The model never touches your actual file. It only sees the text you gave it, reasons over that text, and answers based on patterns it learned during training plus whatever you typed.

The second is a tool that’s connected to your file directly, through a plugin, a code interpreter, or an integration that can open the spreadsheet, run real calculations on it, and show you the output. Some AI-assisted spreadsheet features work this way now, and so do a growing number of “chat with your data” products.

These feel similar from the user’s side. You type a question, you get an answer. But the first one is doing something closer to reading comprehension. The second one is doing something closer to writing a formula for you and running it. Knowing which one you’re using changes how much you should trust the number that comes back.

How the plain chat version works

If you’re just pasting rows into a chat window, the model is reading your data the same way it reads a paragraph of text. It’s not running SUM() or AVERAGEIF() behind the scenes unless it decides to write out that logic step by step and you can see it doing so. It’s predicting what a reasonable answer looks like given the pattern of numbers in front of it.

For small tables, this often works fine. If you paste twenty rows of monthly recurring revenue by customer and ask “which of these customers grew the fastest,” a model can usually eyeball that correctly the same way you could, just faster.

The trouble starts with arithmetic at scale. Ask it to sum two hundred rows of revenue and there’s a real chance it will get close but not exact, especially if the numbers have a lot of decimal places or the rows scroll past what it’s paying close attention to. It’s not that the model is bad at math conceptually. It’s that predicting the next digit in a long sum is a different kind of task than predicting the next word in a sentence, and errors compound.

How the connected, code-running version works

The tools that actually execute code against your spreadsheet are a different story for pure arithmetic. When a model writes a script that opens your file and calls a sum function, the sum function does exactly what sum functions do. The math itself isn’t the weak point anymore.

The weak point moves upstream, to whether the model wrote the right script. Ask it for “total revenue last quarter” and it has to decide what counts as revenue in your sheet, which column holds the date, whether refunds are a separate row or a negative value in the same column, and what “last quarter” means given today’s date. Get any one of those interpretations wrong and you get a number that’s arithmetically perfect and conceptually wrong. It will look confident either way.

This is the same failure mode you’d get from a new hire who’s fast at Excel but doesn’t know your business yet. The formula is fine. The assumption behind the formula is the problem.

What it’s genuinely good at

I use this kind of tool for a few things and they’re not glamorous.

Finding the shape of a mess. Point it at a raw export from a billing system and ask “what looks off in this data” and it’s decent at flagging things a human would eventually notice too: a customer ID that appears with two different spellings of the same company name, a date column that’s a mix of two formats, a currency field that switches from dollars to cents halfway down. That’s the kind of data quality check that’s tedious to do by eye and easy for a model to scan for.

Translating a vague question into a concrete one. “Is churn getting worse” isn’t a query, it’s a feeling. A model can turn that into “compare the monthly churn rate for the trailing three months against the same period last year” and then ask you which definition of churn you actually mean, logo churn or revenue churn. Forcing that clarification is more useful than it sounds, because most of the time you didn’t know which one you meant either.

Writing the formula you were going to write anyway. If you know exactly what you want, “cohort retention by signup month, first twelve months” is a fifteen-minute pivot table job for someone comfortable in a spreadsheet and a ten-second request for a model that can generate the formula or the code. This is the boring, real value. It’s not insight, it’s typing speed.

Where it falls apart

A model has no way to know your business rules unless you tell it. It doesn’t know that “Acme Corp” and “ACME CORPORATION LLC” in your customer column are the same account unless you say so or it happens to notice the pattern. It doesn’t know that a $0 line item means “comped account” in your business and not “free trial that never converted.” It doesn’t know your fiscal year starts in April. Every one of those gaps produces a wrong answer that reads exactly as confidently as a right one.

It also can’t tell you why a number moved unless the reason is sitting in the spreadsheet as data. If your MRR dropped in March, the model can compute that it dropped and even break it down by cohort or plan tier if the columns support it. It cannot tell you that a competitor launched a cheaper plan that month, because that fact isn’t in your spreadsheet. People sometimes ask these tools for the “why” behind a trend and get a plausible-sounding story back. Plausible is not the same as correct. Treat any narrative explanation it gives you as a hypothesis to check against what you actually know happened in your business, not as a finding.

And it will answer a badly framed question without telling you it’s badly framed. Ask for “customer lifetime value” without specifying a time window, a churn assumption, or whether you mean gross or net of costs, and it will pick something reasonable and hand you a number. That number isn’t wrong exactly, it’s just answering a question you didn’t fully ask. This is true of a junior analyst too, but a junior analyst is more likely to ask you what you meant.

A workflow that keeps this useful

What’s worked for me running my own numbers this way:

Keep the source clean before you ask anything. Consistent date formats, one spelling per customer name, a clear column for what’s a refund versus what’s revenue. Every hour spent tidying a sheet saves several rounds of wrong answers later, and this matters more for these tools than it did for a human doing the same analysis, because a person will often ask you what a messy column means and a model often won’t.

Ask for the method, not just the number. Instead of “what’s our conversion rate,” ask it to state the formula it used and which rows it included before it gives you the figure. That one habit catches most of the wrong-assumption problems, because you can spot “oh, it counted trial signups as conversions” before you act on the answer instead of after.

Spot-check against a number you already trust. Pick one metric you’ve calculated by hand before, run it through the tool, and see if it matches. If it does, that buys you some confidence in the rest of the session. If it doesn’t, stop and figure out why before you ask it anything else.

Don’t hand it anything sensitive you wouldn’t otherwise put in a document you can’t fully control where it ends up. If your spreadsheet has customer emails, payment details, or anything covered by a privacy policy you’ve made promises around, check what the specific tool does with uploaded data before you paste it in. That’s a governance question, not a modeling one, and it’s worth five minutes to answer before the first upload.

None of this makes the tool a replacement for actually understanding your own numbers. It’s closer to a fast, literal-minded assistant that will do exactly what you asked, including the parts of the question you didn’t realize were ambiguous. Used that way, on your own spreadsheet, with the assumptions checked, it saves real time on the mechanical parts of the work. Used as a substitute for knowing what your churn or your CLV actually measures, it will hand you a wrong number in a very confident font.

If you want more of this kind of plain-English breakdown of the metrics and tools that actually run a one-person business, you can find the rest of what we cover here.

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