Quick Answer
Yes, the mortgage interest deduction for second homes is limited to interest on total acquisition debt of $750,000 across all homes ($375,000 if married filing separately). This includes your primary residence plus second home mortgages combined, not $750,000 per property.
Best Answer
Robert Kim, CPA
Perfect for people who own both a primary residence and a vacation/second home
How the $750,000 limit works across multiple homes
The mortgage interest deduction limit of $750,000 applies to your total acquisition debt across all qualified residences, not per property. This means if you have a $500,000 mortgage on your primary home and a $400,000 mortgage on your vacation home, you can only deduct interest on $750,000 of that combined $900,000 debt.
Example: Primary home + vacation home scenario
Let's say you have:
Since your total debt ($900,000) exceeds the $750,000 limit, you can only deduct interest on $750,000 of debt:
How to allocate the deduction between properties
According to IRS Publication 936, you allocate the $750,000 limit proportionally based on the outstanding debt on each property:
Key factors that affect your deduction
What you should do
1. Calculate your total acquisition debt across all qualified residences
2. Track which loans qualify — only acquisition debt and qualified home improvement debt count
3. Use our return scanner to ensure you're applying the limits correctly and not missing any deductible interest
4. Keep detailed records of how you use any home equity proceeds, as this affects deductibility
Key takeaway: The $750,000 mortgage interest deduction limit applies to your combined debt on all homes, potentially reducing your deduction by thousands if you have multiple mortgages totaling over $750,000.
*Sources: [IRS Publication 936](https://www.irs.gov/pub/irs-pdf/p936.pdf), IRC Section 163(h)(3)*
Key Takeaway: The $750,000 mortgage interest limit applies to total debt across all qualified homes combined, not per property, potentially limiting deductions for owners with multiple mortgages.
Mortgage interest deduction scenarios based on total debt levels
| Total Mortgage Debt | Deductible Debt | Avg Interest Rate | Max Deductible Interest | Potential Lost Deduction |
|---|---|---|---|---|
| $500,000 | $500,000 | 6.5% | $32,500 | $0 |
| $750,000 | $750,000 | 6.8% | $51,000 | $0 |
| $1,000,000 | $750,000 | 7.0% | $52,500 | $17,500 |
| $1,500,000 | $750,000 | 7.2% | $54,000 | $54,000 |
More Perspectives
Michelle Woodard, JD
Best for prospective buyers who want to understand tax implications before purchasing
Tax planning before you buy
Before purchasing a second home, understand how the mortgage interest deduction limits will affect your tax situation. If your primary residence mortgage is already close to $750,000, you may get little to no tax benefit from second home mortgage interest.
Strategic debt structuring
Consider these strategies when financing a second home:
Alternative tax benefits to consider
Even with limited mortgage interest deductions, second homes offer other tax advantages:
Key takeaway: Plan your second home financing carefully — the combined mortgage debt limit means you may not get the full mortgage interest tax benefit you expect.
Key Takeaway: Strategic planning before purchase can help maximize your mortgage interest deductions within the $750,000 combined debt limit.
Michelle Woodard, JD
Ideal for owners with expensive properties where debt limits significantly impact taxes
When the limits really hurt
For high-value property owners, the $750,000 debt limit can eliminate tens of thousands in annual deductions. If you have $1.5 million in total mortgage debt across properties, you're losing deductions on $750,000 of debt — potentially $45,000+ in non-deductible interest annually at current rates.
Grandfathering rules for pre-2018 debt
If you acquired debt before December 16, 2017, you may qualify for the old $1 million limit. This grandfathering applies to:
Advanced strategies for high earners
Business use election: If you use part of your second home for business (legitimate home office, rental activity), you may be able to deduct interest as a business expense rather than mortgage interest
Debt restructuring: Consider whether to maintain mortgage debt or pay it down based on your marginal tax rate and investment opportunities
State tax implications: Some states have no mortgage interest deduction limits, so the federal limitation may not apply at the state level
Key takeaway: High-value homeowners lose the most from the $750,000 limit and should explore grandfathering rules and alternative deduction strategies.
Key Takeaway: Wealthy homeowners with substantial mortgage debt should explore grandfathering rules and alternative tax strategies to minimize the impact of the $750,000 limit.
Sources
- IRS Publication 936 — Home Mortgage Interest Deduction
- IRC Section 163(h)(3) — Qualified residence interest limitations
Reviewed by Robert Kim, CPA on February 28, 2026
This content is for educational purposes only and is not a substitute for professional tax advice. Consult a qualified tax professional for advice specific to your situation.