1. The Break-Even Calculation
Refinancing costs money upfront — typically 2–5% of your loan amount in closing costs. The break-even point is how long it takes for your monthly savings to recover that cost. Before refinancing, this is the single most important number to calculate.
If you pay $6,000 in closing costs and save $200/month, your break-even is 30 months. Stay longer than 30 months and you come out ahead. Sell or refinance again before then and you lose money on the transaction.
Quick break-even calculator
2. How Much Rates Need to Drop
The old "1% rule" — only refinance if rates drop by at least 1% — is too blunt. The right threshold depends on your loan balance and how long you'll stay. On a large balance, even a 0.5% drop can save you $150–$200/month and break even in under two years.
| Loan Balance | Rate Drop | Monthly Savings | Break-Even* |
|---|---|---|---|
| $200,000 | 0.5% | ~$60/mo | ~8 yrs |
| $200,000 | 1.0% | ~$120/mo | ~4 yrs |
| $400,000 | 0.5% | ~$120/mo | ~4 yrs |
| $400,000 | 1.0% | ~$240/mo | ~2 yrs |
| $600,000 | 0.5% | ~$180/mo | ~3 yrs |
| $600,000 | 1.0% | ~$360/mo | ~1.5 yrs |
*Assumes $6,000 in closing costs at a 30-year term. Use the calculator above for your exact numbers.
The key insight: higher loan balances lower your break-even threshold considerably. A borrower with a $600,000 loan doesn't need to wait for a 1% rate drop — half a point can pay off in under three years.
3. Cash-Out vs. Rate-and-Term Refinance
There are two fundamentally different reasons to refinance — and they have different math.
Rate-and-term refinance
Replace your existing loan with a new one at a lower rate or shorter term. Your loan balance stays roughly the same. The goal is to reduce monthly payments or total interest paid. This is the classic refinance — and the one the break-even calculation applies to directly.
Cash-out refinance
Borrow more than you owe, receive the difference in cash. If you owe $250,000 on a home worth $400,000, you could refinance into a $310,000 loan and receive $60,000 in cash (minus closing costs). Common uses: home improvements, debt consolidation, or major expenses.
Cash-out refinances carry more risk. You're increasing your debt load and resetting the amortization clock. If home values drop after you take cash out, you could end up underwater. Cash-out rates are also typically 0.125–0.25% higher than rate-and-term rates.
Most lenders cap cash-out refinances at 80% LTV — meaning you can only cash out equity above 20% of your home's value. If your home is worth $400,000, lenders will loan up to $320,000, so your maximum cash-out (if you owe $250,000) is $70,000 minus closing costs.
4. Closing Costs: What to Expect and How to Handle Them
Refinance closing costs typically run 2–5% of the loan amount. On a $350,000 loan, that's $7,000–$17,500. Here's what you're paying for:
Rolling costs into the loan ("no-closing-cost refinance") means you borrow slightly more — the lender adds fees to your balance. Your monthly payment is a little higher, but you pay nothing at closing. This works well if you plan to refinance again in a few years before the higher balance compounds.
Paying costs upfront is almost always cheaper over the long run if you're staying put. The break-even timeline is shorter, and you don't pay interest on the fees for the life of the loan.
5. When NOT to Refinance
A lower rate doesn't automatically mean refinancing is the right move. Here are five situations where it probably isn't:
1. You're selling within 2–3 years
If you won't stay long enough to hit the break-even point, you'll spend more on closing costs than you save in payments. Run the numbers: if break-even is 28 months and you're selling in 24, pass.
2. Your loan is nearly paid off
In the last 5–7 years of a mortgage, most of your payment is principal, not interest. Refinancing into a new 30-year loan restarts the amortization clock — you'll pay far more interest over the new loan's life than you'd save on the rate.
3. Your credit score has dropped
If your credit score is significantly lower than when you got your original loan, you may not qualify for a rate low enough to justify refinancing. A drop from 780 to 680 can mean 0.5–1.0% higher rates, erasing the savings.
4. You're extending your term significantly
Refinancing from year 10 of a 30-year mortgage into a new 30-year loan adds 10 years of payments. Even at a lower rate, total interest paid can increase. Consider a 20-year or 15-year refinance instead.
5. The rate difference is too small for your balance
On a $150,000 loan, a 0.5% rate drop saves about $45/month — meaning a $5,000 closing cost takes 9 years to break even. At that point, simply making extra principal payments may achieve more.
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