Does a lower interest rate always save money on a refinance?

No. If you reset to a longer term (for example, 25 years remaining refinanced into a new 30-year loan), the extra years of interest can cancel out the savings from the lower rate: sometimes leaving you paying more in total interest.

What is the refinance break-even point?

It is how long it takes for your monthly savings to recover the closing costs. If closing costs are $5,000 and you save $431/month, you break even in about 12 months.

How do I refinance without paying more total interest?

Keep the term short. Refinancing to a lower rate while also shortening (or at least not extending) the loan term is what turns the lifetime-interest number back in your favor.

Housing

Is refinancing worth it?

Marcus owes $350,000 at 7.5%, and a lender just called, sounding very excited for a Tuesday. Refinance, they say, and the payment drops by $431 a month, with the closing costs paid back in about a year. All of that is true. What the call leaves out is that this refinance costs almost $5,000 more over the life of the loan, and a lot of calculators only show you the first half.

Two separate questions

The first question is whether the lower payment is worth the closing costs, and how quickly you break even. The second is whether the new loan costs less over its whole life. A refinance can pass the first and fail the second, and it happens a lot, usually because the loan term starts over.

A worked example

Here’s the offer Marcus got. He owes $350,000 with 25 years left at 7.5%, and the new loan is 6.25% on a fresh 30-year term, with $5,000 in closing costs. The calculator shows:

Monthly payment: $2,586 → $2,155 (save $431/mo)
Break-even: 12 months to recover the $5,000
Total interest: current loan $425,941 vs new loan $425,804
Net interest savings: −$4,863 (it costs about $4,863 more after closing costs)

A lower rate can cost more interest because a 25-year loan has just become a 30-year loan. Those five extra years of interest almost exactly cancel what the better rate saves. Part of the lower payment comes from stretching the debt out longer, which is the part the phone call didn’t mention.

See both numbers for your loan →Free refinance calculator. Shows the monthly savings and the lifetime cost, with closing costs included. No sign-up.

So when is it worth it?

That depends on which question matters to Marcus. If he needs room in the monthly budget, this refinance does the job, saving $431 a month and paying for itself within a year. If he wants to pay the least interest overall, it fails because the term resets. Refinancing to the lower rate on a shorter term, say a new 20- or 15-year loan, gets him the rate without the extra years, and it’s worth asking the lender for that quote before signing anything.

Where this estimate can be off

The calculator includes closing costs, which quick calculators often leave out, and leaving them out makes a refinance look better than it is. It can’t predict whether rates will fall again or whether you’ll sell early. If you expect to move within a few years, lifetime interest barely matters and the monthly savings is what counts.

These figures come from TheSharpDollar’s Refinance calculator using its sample scenario. Run it with your own balance, rates, term and closing costs.