The Tax Deduction for Mortgage Interest on a Second Home

When you buy a second home, the IRS may let you deduct the mortgage interest you pay on that loan, just like you can for your main home. But the rules are not exactly the same, and a few traps can trip you up if you aren’t careful. Understanding how the deduction works will help you keep more of your money and avoid a surprise tax bill.

First, what counts as a second home for tax purposes? The IRS defines a second home as any property you own besides your main home. It can be a cabin in the woods, a condo at the beach, or even a houseboat as long as it has sleeping, cooking, and bathroom facilities. The key is that you must live in it part of the year for it to qualify as a personal residence rather than a rental property. If you rent it out for most of the year, the tax treatment changes significantly.

The mortgage interest deduction for a second home is limited to the interest on up to $750,000 of total mortgage debt used to buy, build, or improve your first and second homes combined. That limit applies if you took out the mortgage after December 15, 2017, under the Tax Cuts and Jobs Act. If your loans were taken out before that date, the limit is $1 million. So if you already have a $500,000 mortgage on your main home, you can only deduct interest on an additional $250,000 of debt for your second home. If you borrow more than that, you cannot deduct the interest on the extra portion.

Another important rule: the second home mortgage must be secured by the property itself. That means a home equity loan on your main home to buy a second home does not automatically get the same deduction. The interest on that home equity loan is only deductible if you use the money to build or substantially improve the home that secures the loan. If you use it to buy a second home, the IRS treats it as personal debt, and the interest is not deductible. To get the deduction for a second home, you need a mortgage directly on that second property.

What about renting out your second home? Many people buy a vacation property and rent it out for a few weeks or months each year. The IRS has strict rules for this situation. If you rent the home for 14 days or fewer during the year, you do not have to report the rental income at all, and you can still deduct all the mortgage interest as a personal expense. This is a great loophole for owners who use the property themselves most of the time and only rent it for a short period. But if you rent it for more than 14 days, the home is considered a rental property in the eyes of the IRS. In that case, you must report the rental income and deduct expenses in a different way. You can still deduct the mortgage interest, but it becomes a rental expense, and it may be subject to the passive activity loss rules that limit how much you can claim against other income.

If you rent it for more than 14 days and also use it yourself for more than 14 days or more than 10 percent of the rental days, the home is considered a personal residence for tax purposes. This means you can still deduct mortgage interest as a personal item on Schedule A, but only for the portion of the year you use it personally. The interest during rental periods becomes a rental expense. You need to allocate the interest based on the number of days used for each purpose. This gets complicated, and many homeowners hire a tax professional to get it right.

One more thing to watch out for: if you later convert your second home into your main home, the mortgage interest deduction continues to apply, but the $750,000 limit still covers the combined debt on both properties. And if you sell your second home, you generally cannot exclude the capital gain from your income the way you can with a primary residence. The capital gains exclusion of up to $250,000 for a single person or $500,000 for a married couple only applies to your main home. A second home is treated as an investment property for capital gains purposes, and you will owe tax on any profit above your cost basis.

Finally, remember that you can only deduct mortgage interest if you itemize your deductions. Most homeowners today take the standard deduction because the Tax Cuts and Jobs Act nearly doubled it. If your total itemized deductions including the mortgage interest, state and local taxes, and charitable contributions add up to less than the standard deduction, you will not benefit from the mortgage interest deduction at all. For 2024, the standard deduction is $14,600 for single filers and $29,200 for married couples filing jointly. So before you assume you will get a tax break on your second home mortgage, run the numbers.

The bottom line is that the mortgage interest deduction for a second home is available, but it comes with limits, allocation rules, and potential pitfalls if you rent the property. Keep good records of how many days you use the home yourself and how many days you rent it out. Understand the total debt limit across both homes. And if your situation is complicated, consider asking a tax preparer for help. A little planning now can save you headaches at tax time.