How to build your monthly budget in Excel, step by step

A budget in Excel doesn't have to be complicated. A few columns and the consistency of updating it each month are enough to spot patterns, cut spending you didn't realize you had, and plan your savings.

Step 1: the basic columns

Set up a simple table with these columns:

Step 2: log a full month

For a month, write down every transaction as soon as it happens: paycheck, rent, groceries, every small expense. If you wait until the end of the month to "remember it all", the small daily expenses will slip through, and those are exactly the ones worth seeing.

Step 3: add it up by category

Use the SUMIF function to have Excel automatically total how much you spent in each category:

(Adjust the column letters to how you set up your sheet; C for category, D for amount, in this example.)

Step 4: compare it to the 50/30/20 rule

Once you have the three totals, divide each by your net pay to see the real percentage it represents, and compare it to the 50/30/20 split:

Step 5: a simple chart

Select the three totals (needs, wants, savings) and add a pie chart (Insert → Chart → Pie). Seeing at a glance how your money is split helps a lot more than a table of numbers.

Step 6: review it once a month

1. Close out the month in the first few days of the next one, with everything logged.
2. See which category went over its target.
3. Pick a single adjustment for next month, don't change everything at once.
4. Start the new month's sheet by copying the structure, not the data.

Common mistakes when budgeting in Excel

• Too many detailed categories: 4 or 5 categories are enough. With 20, you'll abandon the sheet by month two.
• Logging everything at month's end: you lose precision and small expenses slip through.
• Not logging extra income (a bonus, a side gig): it's also part of the budget for the month it comes in.
• Quitting after a rough month. Come back to the sheet next month, even if the previous one went off track.

What to do with a surplus (or a shortfall)

If a category came in under budget at month's end, don't leave that money "floating" in your everyday account: move it to savings or debt payoff that same day, so it doesn't dissolve into next month. If you came up short, don't abandon the sheet over it: note which category went over and make one adjustment for next month, instead of trying to fix everything at once.

Don't want to build it from scratch? Use the free spreadsheet

FinanciaMente has a free Excel budget spreadsheet, already built with the columns, formulas and pie chart. Just log your transactions each month and the totals and percentages update on their own.

Frequently asked questions

Do I need advanced Excel formulas?

No. SUMIF and a simple division cover everything in this guide.

Can I do this in Google Sheets instead of Excel?

Yes, the same formulas work the same way.

How much time does it take to keep it up to date?

About 5 to 10 minutes a week if you log transactions regularly, and around 20 minutes to close out each month.

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This article is educational, not financial advice. Formulas may vary slightly depending on your version of Excel or Sheets.

Sources

• FinanciaMente, based on the 50/30/20 rule.