United States · Federal tax
Mortgage interest deduction.
See how much mortgage interest you can deduct for 2026, and whether itemizing beats the standard deduction.
Your mortgage and deductions
Your estimate
Worked example
A married couple filing jointly pays $18,000 of interest on a $450,000 loan taken out in 2021. The loan is under the $750,000 limit, so all $18,000 is deductible. Add $10,000 of state and local taxes and $2,000 of charity and itemized deductions total $30,000. The 2026 standard deduction for joint filers is $32,200, so itemizing does not help and the mortgage interest saves $0 in federal tax. If the same couple paid $24,000 of interest, itemizing would total $36,000, which is $3,800 over the standard deduction. At a 22% marginal rate that is about $836.
How the calculation works
- Debt limit. You can deduct interest on the first $750,000 of home acquisition debt ($375,000 if married filing separately). Debt taken out on or before December 15, 2017 is grandfathered under a $1,000,000 limit ($500,000 if married filing separately).
- Grandfathered debt shrinks the room for newer debt. This tool counts grandfathered debt first (up to its limit) and lets newer debt fill whatever is left under $750,000. That is our reading of the IRS limit tables, so check Publication 936 for unusual cases.
- Deductible interest = interest paid × the smaller of 1 and (allowed debt ÷ total debt). Use the average balance for the year.
- Compare deductible interest plus your other itemized deductions with the 2026 standard deduction. The benefit is the excess over the standard deduction × your marginal rate.
| Filing status | 2026 standard deduction | Debt limit (after 2017) | Debt limit (grandfathered) |
|---|---|---|---|
| Single | $16,100 | $750,000 | $1,000,000 |
| Married filing jointly | $32,200 | $750,000 | $1,000,000 |
| Married filing separately | $16,100 | $375,000 | $500,000 |
| Head of household | $24,150 | $750,000 | $1,000,000 |
Sources, as of September 30, 2026: IRS Publication 936, Home Mortgage Interest Deduction (tax year 2025 text, the debt limits); 26 U.S.C. 163(h)(3) (the $750,000 limit is now permanent under Pub. L. 119-21); IRS release IR-2025-103 (2026 standard deduction).
Multiple mortgages, HELOCs and second homes
The limits apply to all your mortgages combined on your main home and one second home, not per loan. Enter the combined interest and the combined average balances. Home equity loan or HELOC interest counts only if the money was used to buy, build or substantially improve the home that secures the loan. If you used it for anything else, leave that loan out of both the interest and balance boxes.
FAQ
Is the $750,000 limit going away?
No. The Internal Revenue Code now applies the $750,000 ($375,000 if married filing separately) limit permanently.
Why does the tool ask for a state and local tax amount?
State and local tax deductions are capped and the cap depends on your income, so enter the amount you can actually deduct rather than what you paid. We do not apply a cap for you.
What about the extra standard deduction for age 65 or blindness?
This tool uses the base 2026 standard deduction only. If you qualify for the additional amounts, add them to your comparison by hand; a higher standard deduction makes itemizing less likely to pay off.
Which number goes in the interest box?
Use the total on your lender's Form 1098, Box 1, for all qualifying loans. Points and mortgage insurance rules differ, so see Publication 936.
Related tools
Estimate only, not tax advice
Results depend on details this tool does not see, including points, the AGI-based limits on other deductions, the alternative minimum tax and state rules. Confirm with IRS Publication 936 or a tax professional before filing.