Refinancing can save you tens of thousands of dollars — or cost you more than you expect. Here's how to tell the difference.
What is mortgage refinancing?
Refinancing means replacing your existing mortgage with a new one — ideally at a lower interest rate, a shorter term, or both. You apply for a new loan, use it to pay off the old one, and start making payments on the new loan instead.
There are two main types: rate-and-term refinancing (you change the rate, the term, or both, but the loan amount stays the same) and cash-out refinancing (you borrow more than you owe and pocket the difference as cash).
The 1% rule (and when to ignore it)
The most common rule of thumb: refinance if you can drop your rate by at least 1 percentage point. Going from 6.5% to 5.5%? The 1% rule says go for it.
But the 1% rule is a rough guideline, not a universal law:
- Large balances amplify small rate drops. On a $500,000 loan, even a 0.5% rate reduction saves ~$160/month. On a $150,000 loan, a 1% drop only saves ~$90/month. The absolute dollar savings matter more than the percentage.
- High closing costs raise the bar. If your lender charges $10,000 in closing costs, you need larger savings to break even. A 1% rate drop might not be enough.
- Short remaining terms lower the payoff. If you have 8 years left on your current mortgage, a rate drop saves less total interest because there's less time for savings to accumulate.
Bottom line: the 1% rule is a decent starting point, but the real question is breakeven.
Breakeven analysis: the number that actually matters
Refinancing isn't free. Closing costs typically run 2–5% of the loan amount — on a $280,000 loan, that's $5,600 to $14,000. The breakeven point tells you when your monthly savings pay back those costs.
Breakeven = Closing Costs ÷ Monthly Savings
Example: $6,000 closing costs ÷ $200/month savings = 30 months (2.5 years).
If your breakeven point is under 3 years, refinancing is almost always worth it (assuming you plan to stay in the home at least that long). Under 5 years is still solid. Over 5 years gets risky — a lot can change.
The critical question people forget: how long do you plan to stay in this home? If your breakeven is 36 months but you're likely to move in 24 months, refinancing loses money.
The hidden cost of extending your term
This is the most common refinancing mistake. You have 22 years left on a 30-year mortgage, and you refinance into a new 30-year mortgage. Your monthly payment drops dramatically — but you just added 8 years of interest payments.
| Scenario | Monthly | Total Interest |
|---|---|---|
| Current: $280K at 6.5%, 22 yrs left | $2,095 | $273,080 |
| Refinance: $280K at 5.5%, 22 yrs | $1,901 | $221,864 |
| Refinance: $280K at 5.5%, 30 yrs | $1,590 | $292,294 |
The 30-year refinance saves $505/month — but costs $19,000 more in total interest than staying put. The 22-year refinance saves less per month ($194) but actually saves $51,000 in total interest.
If you refinance into a longer term, know that you're trading lower payments today for higher total cost. That trade-off can make sense (cash flow matters), but go in with eyes open.
When refinancing makes sense
Refinancing is likely a good move if most of these are true:
- Your rate drops by 0.75–1%+ (or more than $100/month in absolute savings)
- Your breakeven is under 3–5 years
- You plan to stay in the home well past the breakeven point
- Your credit score has improved since your original mortgage
- You want to switch from an adjustable-rate mortgage (ARM) to a fixed rate
When refinancing does NOT make sense
- You're close to paying off the loan. With 5–7 years left, most of your payment is principal. A rate drop saves little total interest.
- The breakeven exceeds your time in the home. Moving in 3 years? Don't refinance if breakeven is 4.
- Closing costs are unusually high. Shop around — costs vary widely between lenders. Get quotes from at least 3.
- Your credit score has dropped. You may not qualify for a rate that makes refinancing worthwhile.
Cash-out refinancing: proceed with caution
Cash-out refinancing lets you tap your home equity — borrow more than you owe and receive the difference as cash. Common uses include home renovations, consolidating high-interest debt, or covering a major expense.
It can be smart when the alternative is worse debt. Consolidating a 22% credit card into a 5.5% mortgage saves real money. But you're converting unsecured debt into debt secured by your home — if you can't make payments, you risk foreclosure.
The danger zone: using cash-out refinancing for lifestyle spending (vacations, cars, consumer goods). You're borrowing against your future self for consumption today. The math almost never works out.
Quick-reference decision checklist
| Scenario | Verdict |
|---|---|
| Rate drop ≥ 0.75–1% | Strong signal |
| Breakeven under 3 years | Almost always worth it |
| Breakeven 3–5 years | Worth it if staying |
| Breakeven over 5 years | Think carefully |
| Extending term significantly | Check total interest |
| Cash-out for debt consolidation | Compare rates carefully |
| Cash-out for lifestyle spending | Avoid |
Run the numbers yourself
Every situation is different. The best way to know if refinancing makes sense for your mortgage is to plug in your actual numbers and see the breakeven point, monthly savings, and total interest comparison. Use our Mortgage Refinance Calculator to compare your current loan against a refinanced one, or the Mortgage Calculator to estimate payments on a new home purchase.