Guide · Spreadsheets
How to make a monthly budget spreadsheet
A budget spreadsheet answers one question: where does the money go each month? This guide shows how to set one up step by step, starting from a ready-made template, so that the totals add up by themselves and you only type in your own numbers.
What a monthly budget spreadsheet needs
You do not need a complicated sheet. A good monthly budget has three parts:
- Income: your pay and any other money that comes in.
- Expenses: rent, food, transport, bills, fun, and what you put aside as savings.
- Left over: income minus expenses. This is the number to watch.
Each line gets two amounts. Planned is what you expect at the start of the month. Actual is what really happened. The gap between them shows you where your plan and your life parted ways, which is the whole point of keeping a budget.
Make it, step by step
Step 1: Open Spreadsheets and choose Monthly budget
Open Octoolo and choose Spreadsheets. Under Start something new, click Monthly budget (“Planned against actual”). It opens as a new workbook called Monthly budget.xlsx, filled with example numbers you will replace.
Step 2: See how it is laid out
The template already has everything from the list above:
- Income at the top: Salary and Other income, with their total.
- Expenses below: Rent, Groceries, Transport, Utilities, Phone and internet, Going out and Savings, with their total.
- Left over at the bottom, in green: total income minus total expenses, planned and actual.
The last column does the comparing for you. For income, Difference is actual minus planned, so a minus sign means less came in than you expected. For expenses, Left to spend is planned minus actual, so a minus sign means you spent more than you planned.
Step 3: Type in your planned amounts
At the start of the month, replace the example numbers in the Planned column with yours. Click a cell, type the amount and press Enter; Tab moves to the cell on the right instead. To rename a category, click its name and type over it.
Not sure what to plan? Look at last month's bank statement, or use the 50/30/20 rule further down this page.
Step 4: Fill in what you really spend
As the month goes on, type what you actually spent into the Actual column. Every total and the Left over line change as soon as you press Enter. In the clip, groceries came in at 430 instead of the planned 450, and Left to spend goes from -62.00 to 20.00 to spare.
Step 5: Add a category of your own
Click a category in the middle of the expenses, not the last one, then open Rows and columns on the toolbar and choose Insert a row below. Because the new row is inside the list, Total expenses includes it on its own.
Type the name, press Tab, type the planned amount, Tab, the actual amount, Tab, and then the sum for Left to spend: an equals sign, the planned cell, a minus and the actual cell, such as =B15-C15. Or select the cell above it and the new one, and press Ctrl+D to copy the formula down.
Step 6: Make the new numbers look like the rest
A new row starts without a number format, so it shows 35 where the others show 35.00. Select its numbers by dragging across them, open the Number format menu (it says Automatic) and choose Number. If you would like a currency sign, choose Currency ($), Currency (€), Currency (£) or Currency (₺) instead.
Step 7: Save it
Press Save (or Ctrl+S), pick a folder and a name, and the budget is saved as an Excel workbook (.xlsx) that also opens in Excel, Google Sheets and LibreOffice. The arrow beside Save has Save as PDF… for a copy to print or send, and Save a copy as CSV for apps that import CSV files.
Reading your budget at the end of the month
Three numbers tell you most of what you need:
- Left over, Actual. Above zero, you lived within your income. Below zero, you spent more than came in, and the difference came from savings or credit.
- The biggest minus in Left to spend. That is the category that ran over. One bad month is normal; the same category over three months running means the plan needs to change, not you.
- Difference on income. If it is often below zero, plan with a lower income figure so you are never caught out.
A simple way to set your planned amounts
If you are starting from nothing, the 50/30/20 rule is a common rule of thumb. Split your income after tax into three parts:
| Part | Share | Of 3,500 | In the template |
|---|---|---|---|
| Needs | 50% | 1,750 | Rent, Groceries, Transport, Utilities, Phone and internet |
| Wants | 30% | 1,050 | Going out, and rows you add: hobbies, holidays, subscriptions |
| Savings and debt | 20% | 700 | Savings |
It is a starting point, not a law: where rent is high, needs take more than half. Notice that Savings sits among the expenses on purpose. Treating it as a bill you pay at the start of the month is the easiest way to make sure it happens.
Keep it going, month after month
A budget earns its keep over several months. At the start of a new month, open last month's file and use Save as Excel workbook… to keep a copy under the new month's name, such as Budget November 2026.xlsx. Then select the Actual amounts and press Delete to clear them, adjust anything in Planned that last month showed was unrealistic, and you are set.
Ten minutes a week to type in what you spent is enough. Doing it all on the last day of the month is harder, because by then nobody remembers what the 38.50 was for.
