How Refinancing Changes Your Mortgage Interest Tax Deduction

When you already have a home loan and you decide to get a new one to replace it, that is called refinancing. Many homeowners do this to get a lower interest rate, to switch from an adjustable rate to a fixed rate, or to take cash out for home improvements or other big expenses. But what happens to your tax situation when you refinance? Specifically, how does it affect the deduction you can take for the interest you pay on your mortgage? The answer depends on what you use the new loan for and how much you borrow.

First, let’s talk about the basic rule for mortgage interest. For most homeowners, the interest you pay on a loan used to buy, build, or improve your main home can be deducted on your federal taxes. The IRS calls this “qualified residence interest.” For a loan that you got after December 15, 2017, you can deduct interest on up to $750,000 of that debt if you are married filing jointly, or $375,000 if you are single. This limit applies to the total of your original mortgage plus any refinance loan. So if you originally borrowed $400,000 to buy your home, and then you refinance for $500,000, the extra $100,000 is not considered acquisition debt — it is treated differently.

Now, when you refinance, the new loan pays off your old loan. The part of the new loan that goes to pay off the old balance is still considered debt used to buy, build, or improve your home. So you can keep deducting interest on that amount, as long as you stay under the $750,000 limit. But here is where it gets tricky: if you borrow more money than what you owed on the old loan, that extra amount is called “cash-out.” For example, if you owed $200,000 on your original mortgage and you refinance for $250,000, you get $50,000 in cash. You can only deduct the interest on that cash-out portion if you use the money to substantially improve your home.

What counts as a substantial improvement? The IRS says it must add value to your home, prolong its useful life, or adapt it to new uses. This includes things like adding a new roof, finishing a basement, installing a new heating system, or building an addition. It does not include routine repairs or maintenance like painting the walls or fixing a leaky faucet. If you use the cash-out money to pay off credit cards, buy a car, or take a vacation, then the interest on that portion of the refinance loan is not deductible. You cannot write off interest on debt that is not related to your home.

Another thing to watch is how the timing affects your deduction. When you refinance, you might have to pay points — these are upfront fees that are basically prepaid interest. On your original purchase mortgage, points are usually deductible in full in the year you bought the home. But on a refinance, you generally have to deduct the points over the life of the new loan. So if you pay $3,000 in points on a 30-year refinance, you can deduct $100 each year for 30 years. There is an exception if you use part of the refinance proceeds to improve your home. In that case, you might be able to deduct a portion of the points right away, tied to the improvement amount. This gets complicated, and many people just spread the deduction over the loan term to keep it simple.

If you refinance multiple times, the rules still apply. Each time you refinance, the new loan becomes the “acquisition debt” up to the amount of the old loan balance that was used for buying, building, or improving the home. The cash-out portion is only deductible if spent on improvements. The same $750,000 limit applies to the total of all debt on your home, including the original mortgage and any refinance. So if you already have $700,000 in acquisition debt and you refinance for $800,000, only $50,000 of the extra amount can be used for improvements and still qualify for the deduction. Anything above that, the interest is not deductible.

You also need to know that the mortgage interest deduction is only available if you itemize your deductions on Schedule A. Most people take the standard deduction instead, especially after the tax law changes in 2018 that nearly doubled the standard deduction. For 2024, the standard deduction is $29,200 for married couples filing jointly and $14,600 for single filers. If your total itemized deductions — including mortgage interest, state and local taxes, and charitable contributions — do not exceed the standard deduction, you get no tax benefit from your mortgage interest at all. So refinancing might not change your taxes much unless you have enough other deductions to make itemizing worthwhile.

Finally, keep good records. When you refinance, save your closing statement (called the HUD-1 or Closing Disclosure) and any receipts for home improvements you make with cash-out proceeds. If the IRS ever asks, you need to prove that the extra borrowed money went toward improving your home and not just paying off other bills. The tax rules are clear but can be confusing. If you are planning a refinance and want to maximize your deduction, it is smart to talk to a tax professional. They can run the numbers for your specific situation and help you decide whether a cash-out refinance makes sense from a tax perspective. Remember, the goal is to lower your monthly payment and build equity, not to create a tax headache.