Real Estate Tax Calc
Full deductibility on Schedule E
Interest on a mortgage used to acquire, build, or substantially improve a rental property is an ordinary business expense deductible on Schedule E of Form 1040. Unlike the mortgage interest deduction for a primary or second home — which is limited under TCJA to interest on up to $750,000 of acquisition debt — there is no dollar cap for rental property. Whether your rental has a $200,000 mortgage or a $2,000,000 mortgage, 100% of the interest is deductible.
Mortgage insurance premiums on a rental property (PMI, MIP) are deductible as an ordinary business expense on Schedule E — separate from the rules for primary residence mortgage insurance, which have their own income limitations.
Cash-out refinances: use of proceeds matters
If you refinance your rental for more than the outstanding balance and take cash out, the deductibility of interest on the excess depends on how you use the proceeds. Proceeds used for the rental property — paying for capital improvements, repairs, operating expenses, or acquiring additional investment property — produce fully deductible mortgage interest. Proceeds used for personal purposes (vacation, paying off a car, funding a personal investment) are not deductible against rental income.
If your refi proceeds are mixed between rental and personal use, you must allocate the interest between the two purposes based on how the money was spent. Keep detailed records of the proceeds deployment.
Points and construction loan interest
Points paid to obtain a rental mortgage cannot be deducted all in year one (unlike points on a primary home purchase loan). Instead, they must be amortized over the life of the loan. A $6,000 point payment on a 30-year rental mortgage produces a $200 deduction per year. Construction and major-renovation loan interest is capitalized during the construction period — added to the property's depreciable basis — and then deducted through depreciation once the property is placed in service, not as a current-year expense.
Worked example: a mixed-use cash-out refinance
You owe $180,000 on a rental and refinance into a new $250,000 loan, pulling out $70,000. You spend $40,000 renovating the rental and $30,000 on a personal car. Interest on the $180,000 that replaced the old rental debt stays fully deductible, and interest on the $40,000 spent on the rental is deductible — together 88% of the new loan. Interest on the $30,000 personal slice (12%) is not deductible against rental income.
If the new loan carries 7% interest — $17,500 of annual interest — you deduct 88%, about $15,400, on Schedule E, and the remaining roughly $2,100 is nondeductible personal interest. This allocation follows the interest tracing rules of Regulation 1.163-8T, which assign interest to whatever the borrowed money was actually spent on, not to the property that secures the loan.
Interest tracing: it's about use, not collateral
The single most misunderstood rule here is that deductibility follows the use of the proceeds, not the asset pledged as security. Money borrowed against your rental but spent on personal consumption is nondeductible; money borrowed against your home but spent to buy or improve a rental can be deducted on Schedule E. The lender's collateral is irrelevant to the tax character of the interest.
This makes documentation essential. When you take cash out, spend it in a clean, traceable way — ideally moving the proceeds through a dedicated account and paying rental expenses directly from it. Commingling refinance proceeds with personal funds invites an allocation dispute on audit and can taint otherwise-deductible interest.
HELOCs, second mortgages, and seller financing
A HELOC or second mortgage — on the rental or on another property — produces deductible interest to the extent the borrowed funds are used in the rental activity. Draw $25,000 on a home-equity line and use it to replace a rental's HVAC system, and that interest is a rental expense traced to the rental. Seller-financed (installment) purchases work the same way: the interest portion of your payments to the seller is deductible, and the seller reports it as interest income.
Private and portfolio loans, including loans from family, follow the same standard — the interest must be on a bona fide debt at a reasonable rate, and the proceeds must fund the rental. Keep the note, the amortization schedule, and proof of how the money was deployed, because informal loans draw extra scrutiny.
Points, prepaid interest, and payoff penalties
Points — loan-origination charges expressed as a percentage of the loan — on a rental mortgage are amortized over the loan term, not deducted up front. A $6,000 charge on a 30-year loan yields $200 per year. If you refinance or pay off the loan early, any unamortized points remaining become fully deductible in the payoff year — a deduction investors routinely forget.
A prepayment penalty the lender charges when you retire a loan early is deductible interest in the year paid. Prepaid interest (interest attributable to a future period) must be spread to the period it covers rather than deducted when paid. These timing rules keep the deduction matched to the periods the interest actually relates to.
Interest during vacancy, turnover, and construction
Mortgage interest continues to be deductible while a rental sits vacant between tenants, provided the property is genuinely held out for rent — advertised, listed, or otherwise available. A normal turnover gap does not suspend the deduction. If you instead pull the property off the market for personal use or for a long renovation with no rental intent, the interest for that period may change character.
Interest during construction or major rehabilitation is different: under the uniform capitalization rules of Section 263A, interest incurred to produce real property is capitalized into the property's basis during the production period and recovered through depreciation once the property is placed in service — it is not a current deduction while you are still building.
Common mistakes to avoid
Three errors dominate. First, deducting interest by collateral rather than by use — putting all the interest from a cash-out refi against the rental even though part of the cash bought personal items. Second, deducting points in full in year one as you would on a primary-home purchase; rental points must be amortized. Third, forgetting unamortized points at refinance, leaving a legitimate deduction on the table.
A fourth, subtler mistake is confusing deductible interest with nondeductible loan principal. Only the interest portion of each payment is deductible; principal reduction is not an expense. Your lender's Form 1098 and year-end statement break out interest, and your amortization schedule confirms it — reconcile them before filing.
Refinancing, assumption, and the Form 1098 you receive
When you refinance a rental, the new loan's interest is deductible to the extent traced to rental use, and any unamortized points from the old loan are deducted in the payoff year. If you assume an existing mortgage or take over a loan in a purchase, interest you pay from the acquisition date forward is deductible; interest that accrued before you owned the property is the prior owner's, not yours.
Each January your lender issues Form 1098 reporting the mortgage interest you paid. Reconcile it to your own records before filing — it should tie to the interest column of your amortization schedule. With more than one rental loan, keep the 1098s separated by property so each property's Schedule E reflects its own interest. When a loan is only partly for the rental (a blended cash-out), the 1098 reports total interest and you must apply your tracing percentage yourself; the form does not do the allocation for you.
Interest, principal, and why cash flow isn't taxable income
A frequent source of confusion is the gap between your mortgage payment and your deduction. Only the interest portion of each payment is deductible; the principal portion builds equity and is never an expense. Early in a loan's life most of the payment is interest, so the deduction is large; late in the loan the payment is mostly principal, and the deduction shrinks even though your check to the lender is unchanged.
This is why a rental can show positive cash flow yet a taxable loss — depreciation plus deductible interest can exceed net rents even while principal paydown quietly builds wealth. Understanding the split helps you plan ahead: as interest deductions fall over the years, taxable income from the property tends to rise, the reason many mature, low-leverage rentals eventually generate a tax bill despite modest cash flow.
Frequently asked questions
Is there a cap on the mortgage interest deduction for rentals?
No. The $750,000 acquisition debt limit applies only to your primary and second home. Rental property mortgage interest is fully deductible regardless of loan size.
Can I deduct mortgage interest if I refinanced and used some proceeds personally?
Only the portion attributable to rental-use proceeds is deductible against rental income. Interest on proceeds used for personal purposes must be traced and excluded.
How do I deduct points on a rental mortgage?
Points on a rental mortgage are amortized (deducted ratably) over the loan term, not fully deducted in year one.
Can I deduct mortgage interest while my rental is vacant between tenants?
Yes, as long as the property is genuinely held out for rent — advertised or listed and available. A normal turnover gap does not suspend the deduction. Pulling the property off the market for personal use is different.
What happens to unamortized points when I refinance a rental?
Any points you have not yet amortized become fully deductible in the year you pay off or refinance the loan. Investors frequently overlook this deduction.
Does the Section 163(j) business-interest limitation apply to my rental?
Most individual landlords are covered by the small-business exception — average annual gross receipts under an inflation-adjusted threshold (about $31 million for 2025) — and are not subject to 163(j). Larger operations can either accept the limitation or elect out as a real property trade or business, which requires using ADS depreciation.
Sources
Educational information and estimates only. Not tax advice. Tax rules change and vary by situation; consult a qualified tax professional before acting.