Budget calculators can be extremely useful when planning your personal finances. The first step in creating a savings plan or a debt management plan is to figure out how much income you are bringing in and how that relates to your expenses. In any situation, you want your income to heavily outweigh your expenses. This isn’t always possible, obviously. A budget calculator helps you by identifying which areas you can cut back and how much you need to cut back. When you use a budget calculator, you can run scenarios and projections to see how your finances would look differently given some variables.

There are numerous budget calculators online. When you use a budget calculator that is built in to a website, you have to keep going back to that site in order to run your numbers again. Plus, there isn’t really a graceful way to save your calculations and fiddle with your figures. One solution to this: make your own budget calculator.

You can make your own budget calculator using any spreadsheet software, such as Google Docs or Excel. Here’s what you do:

Create Your own Budget Calculator

Start a new spreadsheet. Make one section and name it “Income.” In this section of your budget calculator, you’ll be figuring out how much “take home” pay you are making. This is done by applying a simple formula.

Make one field and label it “Monthly Gross Earnings.” For the value, simply type in your monthly earnings before taxes.

Call the field below it “Withholdings.” On average, you have about 28 percent withheld from each paycheck, though this varies widely depending on state and any benefits plans you may be enrolled in. You can customize the withholdings section on your budget calculator to more accurately reflect your situation or you can use the average. For the value of this field, make it the product of 0.28 and the value of the Monthly Gross Earnings box.

Lastly, make a “Monthly Net Income” field. The value of this should be your Monthly Gross Earnings minus your Withholdings.

The next part of your budget calculator will simply be a tally of all of your expenses. Include everything you can think of, including:

• Housing
• Utilities
• Medical Insurance
• Student Loans
• Groceries
• Savings
• Clothing
• Entertainment
• Child Care
• Etc.

Make another formula field that is a total of all these and label it “Monthly Expenses.” Lastly, under a new heading called “Results” make a field in your budget calculator that reads “Monthly Discretionary Income.” This should be your Monthly Net Income minus your Monthly Expenses. You can multiply this final figure by 12 to get your Annual Discretionary Income.

With this budget calculator, you can play around with your expenses and your income to see what your finances would look like after certain changes. Use this to determine how much you should be savings and how much more you need to be making in order to reach your financial goals.