Start herebeginner20 min
Auto-Categorize Your Expenses With AI (Right in Your Spreadsheet)
Export your bank or card transactions, paste the descriptions into Claude or ChatGPT alongside your own list of categories, and the AI labels every row in one pass. An hour of squinting at cryptic merchant names becomes a single review.
Auto-Categorize Your Expenses With AI (Right in Your Spreadsheet)
Export your bank or card transactions, paste the descriptions into Claude or ChatGPT alongside your own list of categories, and the AI labels every row in one pass. An hour of squinting at cryptic merchant names becomes a single review.
Cryptic names, decoded
Your bank export is full of lines like `SQ *BLUE BOTTLE` or `AMZN MKTP US*2X4`. A human has to decode each one. An AI already knows `SQ *` is a **Square** merchant and `AMZN MKTP` is an Amazon purchase. Feed it the description and it assigns a category almost instantly. The trick that makes this reliable: hand it *your* category list instead of asking it to invent one.
Set your buckets first
Before you touch any AI, decide your **categories**. A fixed list is the single difference between tidy books and forty slightly different labels. Keep it short and concrete: - Software, Travel, Meals, Office - Marketing, Contractors, Bank Fees, Other Now every transaction has exactly one home. When the AI is unsure, it drops the item in `Other` and flags it, instead of guessing a brand-new label you have to clean up later.
Get your data ready
Export your transactions from your bank or card as a CSV and open it in Google Sheets or Excel. Keep just three columns: **Date**, **Description**, **Amount**, then add an empty **Category** column. Now delete anything sensitive. You do not need full card numbers to categorize, so removing that column means you never paste it anywhere. Clean inputs make every step after this faster.
The one prompt that does it
Copy your Description column and paste it into Claude or ChatGPT with this brief. The key instruction is "same row order", so the answers line up perfectly when you paste them back. ``` Categorize each transaction into exactly one of these: Software, Travel, Meals, Office, Marketing, Contractors, Bank Fees, Other. Return the category only, one per line, in the same row order. If unsure, use "Other (check)" so I can review it. Descriptions: {paste your Description column here} ``` Drop the results into your Category column. Dozens of rows, sorted in seconds.
Review only the doubts
Now filter your sheet for anything marked **(check)** or `Other`. These are the genuinely ambiguous merchants, a name that could be a client lunch or groceries. Fix just those by hand. This focused review takes a couple of minutes versus the half hour it takes to label every row from zero. You spend your attention only where judgment is actually needed.
Turn it into a summary
The payoff is the report. Ask the AI: "From this categorized list, total the Amount by category and tell me my three biggest spending areas this month." In seconds you get a clean breakdown, and your sheet is ready for your accountant. While you are there, ask it to list **recurring charges**, that is how you catch the subscription you forgot you were paying for.
Run it on last month
Open last month's statement and export it as a CSV. Trim it to Date, Description, Amount, then run the prompt above with your own category list. Reviewing one real month is the fastest way to see how much bookkeeping this quietly removes, and to fine-tune your categories before next month.
Try this now
Your turn: open claude and set up the first step. Just do step one now — the rest takes minutes. Save this guide to pick up where you left off.
FAQ
Is it safe to put my transactions into an AI tool?
You do not need full card numbers to categorize, so delete that column first and never paste it. A merchant name and an amount are low-risk. If this is company data, follow your employer's policy on which tools are approved, and prefer a business account where your data is not used for training.
Will it get the categories right every time?
Mostly, and it gets much better when you hand it your exact category list instead of letting it guess. Ambiguous merchants (a shop that could be office supplies or personal) are where you review. Treat it as a fast first pass you confirm, not a final ledger.
Do I need a paid plan?
No. The free tiers of Claude and ChatGPT handle a month of expenses easily. A paid plan only matters once you are doing this for large volumes every week.
Can it also flag duplicates or unusual charges?
Yes. Ask it to "flag any duplicate transactions and anything unusually large for its category." It is a quick way to catch a double charge or a subscription you forgot you had.