Refinancing can save you thousands — or cost you thousands, depending on timing. The math isn't complicated. Here's the one number that makes the decision obvious.

The break-even point

Every refinance has closing costs — typically 2–5% of the loan amount. To justify refinancing, your monthly savings need to recoup those costs before you sell or pay off the home.

Break-even formula:
Closing costs ÷ Monthly savings = Months to break even

Example: $6,000 in closing costs, $200/month savings = 30-month break-even. If you plan to stay in the home more than 30 months, refinancing makes sense.

The rate drop rule of thumb

The old "1% rule" (only refinance if you drop your rate by at least 1%) is outdated. What actually matters is your break-even vs. your time horizon. But as a rough filter:

  • 0.5% rate drop — usually worth it if you have 5+ years left on the loan
  • 0.75%+ rate drop — almost always worth it on a large balance
  • Less than 0.5% — run the exact math; depends heavily on balance and timeline

When refinancing makes sense

  • Rates have dropped significantly since you bought or last refinanced
  • Your credit score has improved (you may qualify for a better rate)
  • You want to shorten your term (e.g., 30yr → 15yr) to pay off faster
  • You want to cash out equity for home improvements or debt consolidation
  • You're switching from an ARM to a fixed rate for stability

When refinancing doesn't make sense

  • You're planning to sell within 2–3 years (won't hit break-even)
  • You're far into your current loan (you've already paid most of the interest)
  • Your credit has dropped since your original loan (you may not get a better rate)
  • Closing costs are unusually high relative to your balance

The "reset" trap

Refinancing resets your loan term. If you're 10 years into a 30-year mortgage and refinance into a new 30-year loan, you're now paying for 40 years total — even at a lower rate. Consider refinancing into a 15 or 20-year loan to avoid extending your payoff date.

What about closing costs?

Typical closing costs run 2–5% of the loan amount:

  • Origination fee: 0.5–1%
  • Appraisal: $300–$600
  • Title insurance: $500–$1,500
  • Recording fees, taxes: varies by state

Some lenders offer "no-closing-cost" refinances — they roll the costs into your rate instead. You pay slightly more each month but nothing upfront. This is worth it if you're unsure about your timeline.

Run your numbers

The fastest way to know if refinancing makes sense for your specific situation:

Use the MorgCalc refinance calculator →

Enter your current balance, rate, and remaining term — then enter what you could refinance into. You'll see your break-even month, total interest saved, and whether it's worth it.

Bottom line

  • Calculate your break-even point before anything else
  • Compare your break-even to how long you plan to stay
  • Watch out for resetting your loan term
  • Shop at least 3 lenders — rates vary more than you'd think