ARM Index Calculator

Track ARM interest rate adjustments based on index changes.

Calculator Inputs

Enter your details and click "Calculate" to see your results

About This Calculator

Track ARM interest rate adjustments based on index changes. This calculator helps you make informed financial decisions by providing accurate calculations and detailed breakdowns.

Use this tool to plan your finances, compare options, and understand the long-term impact of your financial decisions.

ARM Index Formulas

ARM Rate Calculation

ARM Rate = Index + Margin
  • Index: SOFR, 1-Year Treasury, Prime Rate, etc.
  • Margin: Fixed percentage added by lender (2-3%)

Common ARM Indices

  • • SOFR: Secured Overnight Financing Rate (replacing LIBOR)
  • • Prime Rate: Currently 8.5% (as of most banks)
  • • 1-Year Treasury: US Treasury constant maturity
  • • 11th District COFI: Cost of Funds Index

Example

5/1 ARM tied to SOFR with 2.5% margin:

  • • Current SOFR: 5.0%
  • • Your rate after adjustment: 5.0% + 2.5% = 7.5%
  • • Subject to rate caps (e.g., 2%/6% lifetime)

Frequently Asked Questions

How accurate are these calculations?

Our calculators use industry-standard formulas and are designed to provide accurate estimates. However, actual results may vary based on your specific situation and lender terms.

Can I trust these results?

Yes, our calculations are based on proven financial formulas. However, always consult with a financial advisor for personalized advice.