How to Do a Spending Audit in 30 Minutes

A spending audit is a one-time look at everything you spent last month, so you can see where the money really went and decide what to change. You can do one in 30 minutes in Google Sheets: gather the transactions, categorize them, flag the surprises with filter views, decide on three changes, and save the views so next month's audit takes ten minutes.

What is a spending audit?

A spending audit is a review, not a budget. A budget says what you plan to spend. An audit looks backwards at what you actually spent, line by line, and asks one question of each purchase: was this worth it?

Most people who do one find the same things. A subscription they forgot. A category, usually food delivery or small convenience buys, that's two or three times bigger than they'd have guessed. And a handful of purchases they don't remember making at all.

None of that shows up in a banking app's pie chart, because the pie chart doesn't know which spending you value. Only you do, which is why the audit works best in a sheet where you can mark each row yourself.

How do you do a spending audit in 30 minutes?

Set a timer and work through five steps. The times below assume about one month of transactions, roughly 60 to 120 rows.

The rest of this guide walks through each step.

Step 1: Gather a month of spending (5 minutes)

Create a new Google Sheet with an Audit tab and these headers in row 1:

Then fill A to C from wherever your spending lives:

• If you already track expenses in a sheet, copy last month's rows across. You're ahead of the game, and most of step 2 is already done.
• If you don't, download last month's statement from your bank's or card's website as a CSV file, then use File → Import → Upload and choose Insert new sheet(s). Copy the date, description and amount columns into the Audit tab, and leave out transfers between your own accounts and card repayments so nothing counts twice.
• Cash isn't on any statement. Add what you can remember as rough rows, and see our guide to tracking cash spending for next month.

Keep the whole sheet in one currency. If you spent in another currency while travelling, use the converted amount from your statement.

Step 2: Categorize every row (8 minutes)

Select column D, choose Insert → Dropdown, and add a short list: Rent, Bills, Groceries, Eating out, Transport, Shopping, Subscriptions, Health, Entertainment and Other. Ten or fewer is plenty. Do the same for column E with Keep, Reduce, Cut and Surprise. If you want colored chips and a list you can reuse, our guide to category dropdowns in Google Sheets covers the setup.

Go down the list and pick a category for each row. Don't agonize: if a purchase could be two things, pick the one you'd want to cut from.

Now get the totals. In an empty cell to the right, say H1, paste:

=QUERY(A:F, "select D, sum(C) where C is not null group by D order by sum(C) desc label sum(C) 'Total'", 1)

That lists each category with its total, biggest first. Add a share column next to it (in J2, =I2/SUM(C:C), filled down and formatted as a percent) and you can see at a glance that, for example, eating out was 14% of the month.

Step 3: Flag the leaks with filter views (7 minutes)

This is where the audit happens, and filter views are what make it fast. A filter view is a saved way of looking at the sheet: it hides and sorts rows without changing the data, and you can name it and reopen it later.

Create one with Data → Filter views → Create new filter view, give it a name, then set filters and sorts with the icons in the header row. Build these four:

1. Biggest 20. Sort column C from Z to A. The top 20 rows are often more than half your spending, so flag each one first.
2. Small repeats. On column B, choose Filter by condition → Custom formula is and enter =COUNTIF($B$2:$B,B2)>=3. This shows any merchant you paid three or more times. Coffee, snacks and delivery apps live here.
3. Subscriptions and bills. Filter column D to Subscriptions and Bills. Ask whether you'd sign up for each one again today, at this price.
4. Unflagged. Filter column E to show blanks only. When this view is empty, you've reviewed every row.

As you go, set the Flag column for each row:

• Keep: worth it, no change.
• Reduce: worth it, but less often or cheaper.
• Cut: not worth it. Stop or cancel.
• Surprise: you don't recognize it, or it was more than you thought. Check these against receipts or your email afterwards.

Then add one more QUERY, in L1 for example, to total what you flagged:

=QUERY(A:F, "select E, sum(C) where E is not null group by E label sum(C) 'Total'", 1)

The Cut and Reduce totals are the size of the opportunity. For most people it's a small share of the month, which is the point: you're looking for easy wins, not a lifestyle overhaul.

Step 4: Decide on three changes (7 minutes)

An audit that ends with "spend less" changes nothing. End it with no more than three specific actions, each with a number attached. Write them on a separate Actions tab:

For subscriptions you decide to keep, a subscription tracker spreadsheet puts every renewal date in one place so the next one doesn't catch you out.

Then turn the category totals from step 2 into next month's limits. Take last month's total, subtract the change you just decided on, and that's the budget. If you'd rather start from a rule, the 50/30/20 budget in Google Sheets splits your income into needs, wants and savings, and your audit totals show which bucket is overflowing.

Step 5: Make it a monthly habit (3 minutes)

Filter views are saved with the sheet, so the second audit is mostly reopening them. To set that up:

• Keep one Audit tab. Next month, paste the new month's rows over the old ones (or add them below and filter column A to the new month). The four filter views keep working on the same tab, so there's nothing to rebuild.
• Add a calendar reminder for the first weekend of each month: "10-minute spending audit".
• Check last month's three actions first. Did the cancelled subscription stop? Did delivery drop? That one check is what turns an audit into a habit.

The monthly re-run is faster still when you log spending as it happens instead of rebuilding the list from a statement. With Voice Sheet's Personal Finances template, each expense goes into your own Google Sheet with its category already set, and the monthly budget dashboard shows spending against budget per category, then starts fresh on the 1st. Next month's spending audit then starts at step 3. For bills and subscriptions you've decided to keep, reminders for recurring entries open the entry pre-filled on the day you choose, so they don't go missing from the list. If you're starting from scratch, our guide to tracking expenses in Google Sheets covers the full setup.

Common spending audit mistakes

• Auditing too long a period. A year of transactions takes a weekend and you'll stop halfway. One month, finished, beats twelve months, half done.
• Counting transfers as spending. Card repayments and moves to savings inflate the totals. Leave them out in step 1.
• Judging every coffee. Flag patterns, not single purchases. Eleven coffees a month is a decision; one is not.
• Ending without numbers. "Eat out less" fails. "Four delivery orders a month" can be checked.
• Skipping the follow-up. The second audit, where you check whether last month's changes held, is the one that saves money.