Excel Workbook

Refinance Decision Calculator

A lower rate sounds good — but is it actually worth it? This calculator finds your break-even point, shows your net benefit at 5 and 10 years, and compares lifetime interest on both loans so you can make the call with confidence.

Refinancing feels like a no-brainer when rates drop — but you're paying closing costs today to get savings over time. If you sell the property or rates drop again before you hit the break-even point, you've lost money on the transaction. This calculator makes that math explicit so you're not guessing.

What it calculates

Current monthly payment (from your existing loan details)
New monthly payment (using PMT formula)
Monthly savings after refinancing
Break-even point in months
Net benefit at 5 years and 10 years
Remaining interest on current loan
Total interest on new loan
Lifetime interest difference between the two options

How it works

  1. Enter your current loan balance, interest rate, and remaining term in months
  2. Enter the new loan amount, rate, term, and estimated closing costs
  3. The Results section calculates monthly savings, break-even, and net benefit automatically
  4. A plain-English summary tells you exactly when you'll be ahead and by how much
  5. The lifetime interest comparison shows the full picture — not just the monthly payment
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What's included

  • Refinance Decision Calculator Excel workbook (.xlsx)
  • Current loan and new loan input sections with auto-calculated payments
  • Break-even calculation in months with plain-English explanation
  • Net benefit projections at 5 and 10 years
  • Lifetime interest comparison between current and new loan
  • How It Works tab with a quick-reference guide to break-even ranges
  • Lifetime minor updates included
  • Immediate download after purchase

FAQ

What's the break-even point?

It's the number of months until your accumulated monthly savings equal your closing costs. Before that point, you've spent more on the refi than you've saved. After it, every month you're ahead. If you plan to sell before break-even, the refinance costs you money.

What's a good break-even to aim for?

Under 24 months is generally a clear yes. 24–48 months is reasonable if you're confident you'll hold the property. Over 48 months is worth pausing on — a lot can change in four years. The calculator includes a quick-reference guide in the How It Works tab.

Why does the lifetime interest sometimes go up even with a lower rate?

Because you're restarting the amortization clock. If you've been paying a 30-year loan for 10 years and you refinance into a new 30-year loan, you're adding years back on. Early payments are mostly interest, so total interest often increases even at a lower rate. The calculator shows this explicitly — a shorter term on the new loan often fixes it.

Is this a subscription?

No. One-time purchase, lifetime minor updates included.