Free ARM Calculator Spreadsheet Template
Model adjustable-rate mortgage payments with rate adjustment projections. See how payments change when the introductory rate period ends.
What's Included
- Dashboard with payment projections showing initial payment, adjusted payment, and worst-case payment amounts
- ARM setup with initial rate, adjustment period, rate cap, index margin, and loan term input fields
- Rate schedule with adjustment periods showing how the interest rate and monthly payment change over time
- Payment change projections displaying the dollar difference between introductory and adjusted payment amounts
- Comparison with fixed-rate option and color-coded input fields (yellow) for organized ARM analysis
- Works in Microsoft Excel, Google Sheets, and LibreOffice Calc with no setup required
Preview
See what's inside this template
How to Use This ARM Calculator Template
Enter initial loan terms
Input the loan amount, initial interest rate, adjustment period, and total loan term on the ARM setup sheet.
Set adjustment parameters
Enter the rate cap, index margin, and adjustment intervals. These control how the rate changes after the intro period.
Review rate projections
The rate schedule shows how the interest rate and monthly payment change at each adjustment period.
Compare with fixed rate
The dashboard shows the ARM payment alongside a fixed-rate payment so you can see the potential difference.
Built by Claude AI. Perfected by us.
We use Claude AI to draft each free template, after a deep research. Then our team steps in. We refine the layout, stress-test every formula, fix edge cases, and polish the design until it feels like something we would actually use ourselves. The AI gets us 80% there. The last 20% is all human judgment.
Frequently Asked Questions
What does 5/1 ARM mean?
A 5/1 ARM has a fixed rate for the first 5 years, then adjusts every 1 year after that. Enter these intervals in the setup fields.
How high can the rate go?
Rate caps limit increases per adjustment period and over the loan life. Enter your cap values and the calculator projects the worst-case payment.
What is the index margin?
The margin is added to the index rate (like SOFR) to determine your adjusted rate. Enter the margin from your loan terms on the setup sheet.
Is the worst-case scenario shown?
Yes. The dashboard shows the worst-case payment amount if the rate hits the lifetime cap, alongside the initial and expected adjusted payments.
How do I open this in Google Sheets?
Upload the .xlsx file to Google Drive, then open it with Google Sheets. All formulas and formatting will be preserved.
What license is this template under?
All free templates are released under CC BY 4.0 (Creative Commons Attribution). You can use, modify, and share them freely - including for commercial purposes - as long as you credit FinancialAha.com. They are provided as-is and do not constitute financial advice.
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