Gemini in Google Sheets: how to build a monthly budget

A lot of people in India have a paid AI plan they did not exactly choose. On 30 October 2025 Google announced that eligible Jio customers on Unlimited 5G plans would get Google AI Pro for 18 months at no extra cost, a plan it valued at about ₹35,100. Jio’s own offer page lists “AI Integration in Google Workspace”, naming Gmail, Docs, Sheets and Vids. Then, in December, Google launched a cheaper AI Plus plan in India at ₹199 a month for the first six months, TechCrunch reported.

Most of that access gets used as a chat app. Ask a question, get an answer, close the tab. But the part that earns its keep for an adult with bills to track sits inside a spreadsheet, and hardly anyone opens it. So here is one job, done start to finish: a monthly budget, built with Gemini in Google Sheets.

First, check the button is there

Open Google Sheets on a computer, signed in with the Google account your plan is attached to. For the Jio offer, that is the Gmail ID you registered through the MyJio app. Start a blank spreadsheet and look at the top right for Ask Gemini. Click it and a side panel opens with a prompt box at the bottom.

No button? Then your plan probably does not include it. Google’s plan comparison page promises help to “work smarter in Docs and Sheets” on AI Pro and above. For AI Plus, the same page only mentions proofreading in Gmail, so do not assume. Google also says these features are for ages 18 and up, and only in select languages.

Build the budget in five prompts

Type each of these into the side panel. They are written the way Google’s own help examples are: plain, specific, one job at a time.

1. The skeleton. “Create a table to track a month of household spending in rupees, with columns for date, item, category, payment method and amount.” Gemini drafts the table in the panel. Click Insert to put it on the sheet.

2. The categories. “Create a dropdown in column C with options Groceries, Rent, Transport, School fees, Eating out, Other.” For actions like this, Gemini shows an action preview card, and nothing changes until you click Apply. Change the list to match your own life. That is the point of doing it yourself.

3. The data. This bit is yours. Type the month’s spending in, or paste it from wherever you keep it. Leave out account numbers and anything else you would not write on a notice board, because nothing in this budget needs them.

4. The totals. “Create a pivot table that shows the sum of amount by category.” Pivot tables are one of the five editing actions Google added to Gemini in Sheets in May 2025, along with dropdowns, conditional formatting, filters and sorting. You will get one row per category with its total, which is most of what a budget is.

5. The warning light. “Highlight rows where amount is greater than 2000.” Pick a number that means “I should have noticed that” for your household. It is the same pattern as Google’s example prompt, “Highlight rows where sales are greater than 500”.

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Running a small business rather than a household? Nothing changes except the columns. A home tiffin service might want date, customer, item, quantity, amount received, and cash or UPI. Then ask for the pivot table by customer, and you can see who still owes you.

Where it goes wrong, and how to catch it

Google is blunt about this in its own help page: Gemini “may suggest inaccurate or inappropriate information”, and it should not be treated as financial or other professional advice. In a spreadsheet the mistakes are rarely dramatic. They are quiet. A range that stops one row short, so the last week of the month vanishes from the total.

So check one number by hand. Pick your smallest category, add it up on a calculator, and compare it with the pivot table. If they match, the structure is probably right. If they do not, click into the formula or the pivot table’s range and look at which rows it covers. This takes two minutes and it is the whole difference between using the tool and trusting it. (If you want the longer reason why AI gets confident things wrong, we explained it in why ChatGPT makes things up.)

Two quirks worth knowing before you rely on this every month:

• Charts do not update. Ask for “a pie chart of spending by category” and Gemini will make one, but Google’s help page says the generated chart “doesn’t link or respond to changes in the original data set”. Fine for a one-off look. For a chart that stays live, insert it yourself from the pivot table using the normal Insert menu.
• The conversation forgets. Your side-panel history is lost when you reload the browser, close and reopen the file, or go offline. So add a second tab called Prompts and paste in the five that worked. Next month you copy the sheet, clear the data, and you are done.

The prompt that is actually worth asking

Once the numbers are in and checked, try: “Identify trends in this table.” Google lists it as an example, and it is where the tool stops being a formula typist and becomes something to think with. It might point out that eating out doubled in the last fortnight, or that transport is higher than rent. Treat what it says as a question to look into, not a verdict, and check the numbers it quotes against your pivot table.

Google’s advice on prompting, from a 2024 post on its blog, is to iterate, and it notes that the most successful prompts average around 21 words. That matches what you will find here. Short and specific beats clever. If a result is wrong, do not start again. Say what is wrong in one sentence and ask again.

If you do this once this week, with last month’s spending, you will know whether the plan you were handed is worth keeping when the free months run out. That is a better test than any review.