How to Use Google Sheets to Track a Monthly Budget in 20 Minutes

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Money often slips away in small, forgettable amounts: a snack here, a delivery fee there, a subscription you meant to cancel. By the end of the month, the total surprises you, even though no single purchase felt big. A simple Google Sheets budget fixes that, because it puts your income, your planned spending, and what is left in one place you can check in a minute.

In this guide

• Step 1: Open a blank sheet and name it (3 minutes)
• Step 2: List your income and regular costs (5 minutes)
• Step 3: Add totals with two simple formulas (5 minutes)
• Step 4: Enter actual spending and check it (4 minutes)
• Step 5: Keep it going with a weekly check (3 minutes)
• Common mistakes to avoid
• Quick check
• Final thoughts

Step 1: Open a blank sheet and name it (3 minutes)

Go to sheets.google.com and sign in with the Google account you already use for Gmail or Docs. On the Sheets home page, click Blank spreadsheet, the large tile with a plus sign.

At the top left, click Untitled spreadsheet, type Monthly Budget, and press Enter. A clear name matters, because you will look for this sheet again next month, and you do not want to hunt through untitled files.

Now set up your headings. In the first row, type Category in cell A1, Planned in B1, and Actual in C1. Then click View, then Freeze, then 1 row, so those headings stay visible when you scroll down.

Step 2: List your income and regular costs (5 minutes)

Start with income, because everything else is measured against it. In cell A2, type Income, and in B2, type your take-home pay for the month. For the example in this guide, that is £2,200.

Then list your regular costs in column A, one per row, with the planned amount in column B. Try this example to start:

• Rent: £850
• Groceries: £300
• Transport: £130
• Bills: £210
• Fun: £110
• Savings: £200

Those planned costs add up to £1,800. Put savings in the list on purpose, as a planned row, not as whatever happens to be left at the end of the month. If a cost does not fit neatly, put it in the closest row for now. You can split a row later, once you can see which one keeps going over.

Step 3: Add totals with two simple formulas (5 minutes)

Formulas sound technical, but you only need two, and both start with an equals sign. In A9, type Total out. Then click cell B9 and type =SUM(B3:B8) and press Enter. That adds the six planned costs above it, from row 3 to row 8.

Next, click cell B10, type Left to assign in A10, then in B10 type =B2-B9 and press Enter. That subtracts your planned total from your income. With the example numbers, it should show £400: £2,200 minus £1,800.

That £400 is not free money. It is the amount you have not assigned yet, so you can see it, decide what it is for, or keep it as a buffer for an uneven month. If the number is negative, your plan already spends more than your income, and that is useful to know now, not on the last day of the month.

To show the amounts as money, select cells B2 to B10, click Format, then Number, then Currency. The numbers stay the same, but they now read as pounds, which makes the sheet much easier to scan.

Step 4: Enter actual spending and check it (4 minutes)

A plan only helps if you compare it with what really happened. As the month goes on, type what you actually spent in column C, next to the matching category in column A. A grocery shop of £72 goes in the Groceries row, not in a new row you invent on the spot.

At the end of the month, add the same two totals for the Actual column. In C9, type =SUM(C3:C8), and in C10, type =B2-C9. The first shows what you actually spent in total, and the second shows what is left from your income after that spending.

Now compare each row, side by side. If Groceries planned £300 but actual £340, that row is £40 over, and you can see it without doing any maths in your head. Do not delete the row or change the planned number after the fact. Note the gap, and either move money from a row that came in under, or change next month’s plan for that one row.

Step 5: Keep it going with a weekly check (3 minutes)

Pick one day each week, open the sheet, and spend two minutes updating column C. That short, regular check beats one long session at the end of the month, when receipts are lost and small amounts are already forgotten.

Each week, look at just three things: the row that is closest to its planned limit, the Left to assign cell, and any row you have left blank. If a row is blank, you have not tracked it yet, and that is the row to fill in first.

When a new month starts, do not start a new sheet from scratch. Make a copy with File, then Make a copy, rename it for the new month, and clear only the Actual column. Your categories, planned amounts, and formulas carry over, and you only need to adjust the numbers that changed.

Common mistakes to avoid

• Listing every tiny purchase as its own row, then giving up because the sheet takes too long to update.
• Leaving savings out of the plan, then wondering why nothing is left at the end of the month.
• Typing totals by hand instead of using SUM, so one typo throws out the whole sheet.
• Changing the planned amount after spending, which hides the gap instead of showing it.

Quick check

You should finish with a sheet named Monthly Budget, an Income row, your cost rows including Savings, and two totals that add up: Total out and Left to assign. If Left to assign looks wrong, click the cell and check that the formula still reads =B2-B9, and that the SUM range still covers all your cost rows.

One common error is easy to spot: a total that stays at £0 even though you typed amounts above it. That usually means the formula was typed without the equals sign, or the range misses a row. Add the equals sign first, then check the row numbers in the brackets, and press Enter again.

Final thoughts

Try this with this month’s numbers, even if the month is already half over. A rough sheet you actually update will tell you more than a perfect sheet you never open. After one month, you will know which rows need splitting, which planned amounts were guesses, and how much buffer you really need.

Related guide

To turn a monthly plan into a weekly one, see also: How to Use ChatGPT to Plan Your Week in 20 Minutes.

For a simple first guide to an everyday tool, see also: How to Use ChatGPT for Everyday Tasks: A Simple Step-by-Step Guide.