How to Create a Mortgage Calculator With Apple Numbers '09. If you're going to buy a house or refinance your current mortgage, it's always a good idea to work out all the details, including the possible payments based on your interest rate, down payment and the length of the mortgage. Apple's iWork comes with a spreadsheet program called "Numbers" and included is a Mortgage Calculator template. It'll calculate your monthly payment based on interest rate and down payment and will also work out an amortization schedule, so you can see how much of your payment each month is going towards interest and principle. Read on for how to calculate your mortgage payments.
Launch Apple's Numbers '09 by clicking on its icon in the dock or go to your Applications and locate it in the iWork '09 folder.
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Select "Personal Finance" from the Template Chooser Menu.
Click on the "Mortgage" template and hit the "Choose" button at the bottom right of the Template Chooser.
Replace the numbers in bold (purchase price, percent down payment, interest rate and mortgage length). For this article, the purchase price is $220,000, down payment is 15 percent and the interest rate is 4.75 percent for a 30-year loan. Numbers will recalculate the other values automatically.
Look at the "Possible Payments" area and you can see a monthly payment comparison of other loan amounts and interest rates.
Click on "Data" on the left side of the Numbers window. This will display the sheet with the amortization schedule.
Type in your income tax rate. If you don't know what your tax bracket is, check Resources below for a link that shows your tax bracket based on your tax filing status and income for the year. This example uses 28 percent.
Look at the Monthly Data-this shows you how much of your monthly payment is going to interest and principle, and keeps track of your cumulative payments. It also calculates your tax savings (this may not be applicable for all areas).
Save your document.
Things You'll Need
Apple Macintosh Computer running Mac OS 10.4.11 +