For tax purposes, a second home is a property you use personally for more than the greater of 14 days or 10% of the days you rent it out at a fair market price during the year.1Office of the Law Revision Counsel. 26 USC 280A – Disallowance of Certain Expenses in Connection With Business Use of Home, Rental of Vacation Homes, Etc – Section: Use as Residence Meet that threshold and the IRS treats the property as a residence, which unlocks mortgage interest and property tax deductions and limits how rental losses can be used. Fall short and the property is reclassified as a rental or investment, with a different (and often less favorable) set of rules.
The Personal-Use Test
Run the numbers for your own year. Rent the place for 200 days and you need at least 21 personal-use days, because 10% of 200 beats 14. Rent it for only 60 days and 14 personal days is enough, because 14 beats 10% of 60. Rent it not at all and any personal use qualifies.
Days a family member spends at the property count as your personal use, even if the relative pays you something. The only exception is when the relative pays a rent that genuinely reflects the local market for a comparable property.1Office of the Law Revision Counsel. 26 USC 280A – Disallowance of Certain Expenses in Connection With Business Use of Home, Rental of Vacation Homes, Etc – Section: Use as Residence Days you spend at the property working full-time on repairs or maintenance do not count as personal use, so a weekend fixing the deck won’t add to your occupancy total.
Keep a simple log of every night you or a family member stays. The classification hinges on this count, and if audited, the burden of proof is on you.
The 14-Day Rental Exception
If you rent the property for fewer than 15 days during the year, you owe no federal income tax on the rent you collect and you don’t report it at all.2Internal Revenue Service. Publication 527 (2025), Residential Rental Property Two weeks of peak-season bookings in a popular vacation area can be worth several thousand dollars, entirely tax-free.
In a year like that, the IRS treats the home as if it were never rented. You still deduct mortgage interest and property taxes on Schedule A as you would for any personal residence.2Internal Revenue Service. Publication 527 (2025), Residential Rental Property The trade-off: you cannot deduct expenses tied to the rental activity itself, such as cleaning fees or a property manager’s commission on the booking. For owners who rent only occasionally, this arrangement is heavily favorable.
Rental Income Beyond 14 Days
Cross the 15-day rental threshold and every dollar of rent goes on Schedule E. You can offset that income with expenses like insurance, repairs, utilities, and a share of your mortgage interest and property taxes, but the shared costs have to be allocated between personal-use days and rental days.3Internal Revenue Service. 2025 Instructions for Schedule E (Form 1040) If you personally used the home 30 days and rented it 120, then 120 out of 150 total use-days, or 80%, of shared expenses fall on the rental side.
The personal-use test then controls whether rental losses can shelter other income. If the property still qualifies as your residence, rental deductions cannot exceed rental income. You cannot generate a paper loss.4Office of the Law Revision Counsel. 26 USC 280A – Disallowance of Certain Expenses in Connection With Business Use of Home, Rental of Vacation Homes, Etc – Section: Limitation on Deductions If personal use falls below the threshold and the property is not your residence, the at-risk and passive-activity-loss rules take over, which can allow losses under specific conditions but carry their own complications.
Mortgage Interest and Property Taxes
Mortgage interest on a second home is deductible on the same terms as your primary residence, but the two share one borrowing cap. For mortgages taken out after December 15, 2017, the combined acquisition-debt limit is $750,000, or $375,000 if married filing separately.5Internal Revenue Service. Publication 936 (2025), Home Mortgage Interest Deduction Owe $600,000 on the primary home and only $150,000 of second-home debt generates deductible interest. Older mortgages remain under the previous $1 million cap.
The IRS defines a “qualified home” broadly. Boats, RVs, and mobile homes can all count, provided the property has sleeping, cooking, and toilet facilities.5Internal Revenue Service. Publication 936 (2025), Home Mortgage Interest Deduction A houseboat with a galley and a head qualifies. A bare sailboat without a stove does not.
Property taxes on the second home are deductible but fall under the combined state and local tax (SALT) cap. For 2026, that cap is approximately $40,400 for taxpayers with modified adjusted gross income below roughly $505,000, with a phase-down above that level, and it is scheduled to revert to $10,000 starting in 2030. Because the single cap covers state income tax, local income tax, and property taxes on all your real estate combined, owners in high-tax states may have little cap space left for the second-home portion.
Capital Gains When You Sell
Selling a second home triggers capital gains tax on the profit, and no automatic exclusion applies. The $250,000 exclusion, or $500,000 for joint filers, requires that you owned and used the property as your main home for at least two of the five years before the sale.6Office of the Law Revision Counsel. 26 USC 121 – Exclusion of Gain From Sale of Principal Residence A property you’ve only ever used as a vacation retreat doesn’t clear that bar. The gain is reported on Schedule D as a capital asset.7Internal Revenue Service. Capital Gains, Losses, and Sale of Home
Some owners try to convert a second home into a primary residence for two years before selling. That can work, but the tax code reduces the exclusion for periods of “nonqualified use” after 2008. Any post-2008 years when the property was not your main home get a proportional share of the gain, and that portion stays taxable.8Internal Revenue Service. Publication 523 (2025), Selling Your Home Owned for ten years, used as a vacation home for eight, then lived in for two? Roughly 80% of the gain remains taxable. The math rarely works out as well as owners expect.
A 1031 like-kind exchange, which lets you defer gains by rolling the proceeds into a replacement property, generally does not apply to a home used mostly for personal enjoyment. Both the property sold and the replacement must be held for investment or business use.9Internal Revenue Service. Like-Kind Exchanges Under IRC Section 1031 A vacation home where the family spends holidays fails that test. To preserve 1031 eligibility, the property has to be rented consistently and personal use kept below the level that would make it your residence under Section 280A.
A Word on Lender Definitions
The tax definition is not the only one that matters. Mortgage lenders use their own “second home” standard, which focuses on location, property type, and whether you control who occupies the home. It’s possible to meet the IRS definition of a second home while a lender classifies the same property as an investment for financing purposes, and vice versa. If you plan to rent frequently or buy near your primary residence, verify how the lender will classify the loan before closing, because financing terms and tax treatment can pull in different directions.