Mortgage Interest Tax Deduction: What Qualifies and How Much

If you’re a homeowner in 2026 and you’re not sure whether deducting mortgage interest still makes sense for you, you’re not alone. The standard deduction keeps climbing, home prices have shifted, and the rules haven’t changed since 2017. Here’s what actually qualifies, how much you can save, and whether itemizing is even worth your time this year.

The 2026 Standard Deduction Problem: Why This Matters More Than Ever

The single biggest factor in whether the mortgage interest deduction helps you is whether your total itemized deductions exceed the standard deduction. For 2026, those standard deduction figures are:

That’s a high bar to clear. If you bought a modest home with a low interest rate during 2020-2021, your annual mortgage interest might only be $8,000-$12,000. Even combined with state and local taxes (capped at $10,000), property taxes, and charitable donations, plenty of homeowners still can’t beat the standard deduction.

The deduction tends to benefit you most if:

• Your mortgage balance is large (think $400,000+)
• Your interest rate is above 5%
• You have significant other itemizable expenses
• You’re in a higher tax bracket (24% or above)

If none of those apply, you may be better off taking the standard deduction and moving on. No shame in that.

How the Math Actually Works: Calculating Your Mortgage Interest Deduction

Your lender sends you Form 1098 every January, showing exactly how much interest you paid during the prior year. That number is your starting point, but it’s not always the number you get to deduct.

Here’s the key rule: you can only deduct interest on the first $750,000 of mortgage debt ($375,000 if married filing separately). If your loan is under that threshold, you can deduct the full interest amount shown on your 1098. If it’s over, you need to do some proportional math.

Example with a $900,000 mortgage at 6.5% interest:

1. Total interest paid in year one: roughly $58,200
2. Eligible portion: $750,000 / $900,000 = 83.3%
3. Deductible interest: $58,200 × 0.833 = approximately $48,500

What that’s actually worth in tax savings:

Those are real dollars back in your pocket. But notice how the deduction is worth significantly more to someone in the 35% bracket than someone at 22%. The mortgage interest tax deduction is, by design, more valuable to higher earners.

The Grandfathered $1 Million Limit: Does It Still Apply to You?

If you took out your mortgage before December 16, 2017, your deduction limit is $1 million ($500,000 if married filing separately). That’s a meaningful difference for people carrying larger loans from that era.

A few things to keep in mind about this grandfathered status:

• Refinancing matters: If you refinanced a pre-December 2017 mortgage, you generally keep the $1 million limit, but only up to the balance of the old loan. Any additional cash-out amount falls under the $750,000 rules.
• The binding contract exception: If you had a written binding contract before December 16, 2017, to close on a home, and you actually closed before April 1, 2018, the IRS treats your mortgage as pre-December 2017.
• Second mortgages and HELOCs: Under current rules, home equity debt is only deductible if the funds were used to buy, build, or substantially improve the home securing the loan. That “consolidate your credit card debt with a HELOC” strategy doesn’t generate deductible interest anymore.

If you’re sitting on a pre-2017 mortgage with a rate below 4%, refinancing into today’s higher rates just to “restart” your deduction would almost certainly cost you more than you’d save. Run the numbers carefully or talk to a tax professional before making that call.

What Types of Properties and Payments Actually Qualify?

The IRS is surprisingly flexible about what counts as a “home” for this deduction, but rigid about other requirements. Here’s the breakdown:

Qualifying property types:

• Houses, condos, co-ops, and apartments
• Mobile homes and house trailers
• Houseboats
• Any structure with sleeping, cooking, and toilet facilities

Qualifying payments beyond standard interest:

• Mortgage points: Whether you paid them upfront at closing or they’re being amortized over the life of the loan
• Late payment charges: As long as the charge isn’t for a specific service your lender performed
• Prepayment penalties: If you pay off your mortgage early and get hit with a penalty, that penalty is generally deductible as interest
• Construction loan interest: During the period your home is being built

What does NOT qualify:

• Interest on a loan not secured by the home itself (personal loans used for a down payment, for instance)
• Interest on mortgage debt exceeding the applicable limit
• Homeowner’s insurance premiums
• HOA fees

Can You Deduct Interest on a Second Home?

Yes, but the rules have a catch. Your $750,000 limit applies to the combined mortgage debt on your primary and second home. So if you owe $500,000 on your main house and $400,000 on a vacation property, your total qualifying debt is capped at $750,000, not $900,000.

If you rent out the second home, there’s a usage requirement: you must personally use the property for the longer of either 14 days or 10% of the total days it was rented. Fall below that threshold, and the property is treated as a rental, which shifts you into an entirely different set of tax rules on Schedule E.

Red Flags That Could Trigger IRS Scrutiny

Claiming the mortgage interest deduction is straightforward for most people, but certain situations raise flags:

• Deducting interest on a third property: You only get the deduction on two homes. Period.
• Mismatched 1098 numbers: Your lender sends the IRS a copy of your Form 1098. If the interest amount on your return doesn’t match, expect a letter.
• Deducting interest on debt used for non-home purposes: If you took a cash-out refinance and used the money to buy a boat, that portion of the interest isn’t deductible. The IRS can and does trace the use of funds.
• Claiming the deduction while also taking the standard deduction: You can’t do both. It’s one or the other.

Keep your closing documents, 1098 forms, and records of any home improvements funded by equity loans. If you use part of your home as an office or rent out a portion, document the square footage and income carefully.

The Step-by-Step Claim Process for 2026

Filing for the deduction isn’t complicated, but it requires itemizing. Here’s what to do:

1. Collect your Form 1098 from your lender (arrives by early February)
2. Gather other itemizable expenses: state/local taxes paid, charitable contributions, medical expenses exceeding 7.5% of AGI
3. Compare your total itemized deductions to the standard deduction for your filing status
4. If itemizing wins, complete Schedule A of Form 1040
5. Enter your deductible mortgage interest on line 8 of Schedule A
6. If you paid points, report them on line 8a (if deducting in full) or amortize them across the loan term

Tax software handles most of this automatically, but understanding what’s happening behind the scenes helps you catch errors.

2026-Specific Considerations: What’s Changed and What Might Change

The Tax Cuts and Jobs Act provisions that set the $750,000 cap and eliminated the separate home equity interest deduction are currently scheduled to expire after 2025. Congress has been debating extensions and modifications throughout 2025 and into 2026, so the rules could shift.

What to watch for:

• Possible return to the $1 million limit if TCJA provisions sunset without replacement
• Potential restoration of home equity interest deductions regardless of how funds are used
• Changes to the standard deduction that could make itemizing more or less attractive

None of this is settled yet. For your 2025 tax return (filed in early 2026), the $750,000 limit and current rules still apply. Check IRS.gov or consult a tax advisor for updates affecting your 2026 income tax filing.

Frequently Asked Questions

Can I claim the mortgage interest deduction if I’m in the military or clergy?

Yes. If you receive a nontaxable housing allowance through military service or a ministry position, you’re still eligible to deduct mortgage interest on your qualified home. The housing allowance doesn’t disqualify you, though you can’t deduct interest that was paid using tax-exempt income in certain narrow situations. Check IRS Publication 936 for the specifics.

What happens if I get divorced and we both pay the mortgage?

If a divorce decree requires one spouse to pay the mortgage on a jointly owned home, the interest payments may be treated as deductible mortgage interest for the person making them, or potentially as alimony depending on the agreement’s structure. Both parties should keep detailed records and consult a tax professional, because the classification affects both people’s returns.

Can I deduct mortgage interest if I co-own a home with someone who isn’t my spouse?

You can deduct only the portion of interest you actually paid. If you and a non-spouse co-owner split payments equally, you each deduct your half. You’ll need your own records since the 1098 typically goes to just one borrower. The person who receives the 1098 should provide the other with documentation of their share.

Is it worth itemizing just for the mortgage interest deduction?

Only if your total itemized deductions exceed the standard deduction for your filing status. For a married couple in 2026, that means clearing roughly $31,400. Take 15 minutes this week to add up your mortgage interest, state and local taxes (up to $10,000), charitable giving, and any qualifying medical expenses. If the total falls short, take the standard deduction and save yourself the paperwork.

This article provides general tax information and is not a substitute for personalized advice from a qualified tax professional or financial advisor. Tax laws are subject to change, and individual circumstances vary. Consult a CPA or enrolled agent for guidance specific to your situation.