CalculateRealEstateROI

Calculator Guide

Mortgage Impact Analyzer

A 1% rate change can shift a deal from profitable to negative cash flow. The Mortgage Impact Analyzer shows the full ripple effect across payment, interest paid, and amortization schedule.

Reviewed by Keiron Brown, Founder & Editor, CalculateRealEstateROI · Educational estimates only — not investment, financial, tax, or legal advice

Ready to run the numbers?

Open the Mortgage Impact Analyzer →

Inputs

  • Loan Amount. Purchase price minus down payment.
  • Interest Rate. Annual percentage rate.
  • Term. Loan length in years (15, 20, 30).

Outputs

  • Monthly P&I. Principal and interest payment.
  • Total Interest. Lifetime interest paid over the loan term.
  • Amortization Chart. Year-by-year principal vs interest split.

Formulas

  • Monthly P&I
    L × (r(1+r)^n) ÷ ((1+r)^n − 1), where r = monthly rate, n = months

Best Practices

  • Run scenarios at +/- 1% to understand rate risk before locking.

Common Pitfalls

  • Comparing 30-yr to 15-yr payments without accounting for the equity buildup difference.

Frequently Asked Questions

Should I pay points?
Calculate the break-even (cost of points ÷ monthly savings). If you'll hold past break-even, points usually win.