Mortgage Interest Deduction Calculator
Calculate how much you can save by deducting mortgage interest on your taxes. Compare the total tax benefit of itemizing vs the standard deduction, and see if your mortgage makes itemizing worthwhile.
Incremental Tax Savings from Itemizing
$1,800
Itemizing saves $1,800 more than the standard deduction
| Item | Amount |
|---|---|
| Annual Mortgage Interest | $26,000 |
| Deductible Interest (limit: $750,000) | $26,000 |
| Total Itemized Deductions | $39,000 |
| Standard Deduction | $31,500 |
| Better Option | Itemize ($39,000) |
Interest Tax Savings
$6,240Additional Savings vs Standard
$1,800Mortgage Limit
$750,000Mortgage interest is deductible on loans up to $750,000 for your situation. Property taxes are subject to the $10,000 SALT cap ($5,000 MFS). The tax benefit shown assumes you itemize deductions. This calculator provides estimates — consult a tax professional for exact calculations.
Frequently Asked Questions
What is the mortgage interest deduction limit?
For mortgages originated after December 15, 2017, you can deduct interest on up to $750,000 of mortgage debt ($375,000 if married filing separately). Mortgages taken out before that date are grandfathered at the old $1 million limit ($500,000 MFS). This limit applies to the combined balance of first and second mortgages on your primary and secondary residences.
Is it still worth itemizing for mortgage interest?
With the higher standard deductions under TCJA ($30,000 MFJ for 2025), many homeowners find that the standard deduction exceeds their total itemized deductions. Itemizing tends to be beneficial for homeowners with large mortgage balances, high property taxes, significant charitable donations, or those living in high-cost areas.
What is the SALT cap and how does it affect me?
The State and Local Tax (SALT) deduction is capped at $10,000 ($5,000 MFS) for combined state/local income taxes and property taxes. This cap, introduced by TCJA in 2018, significantly impacts homeowners in high-tax states who previously deducted much more. The cap is currently set to expire after 2025.
Can I deduct interest on a HELOC or second mortgage?
Interest on a HELOC or second mortgage is deductible only if the loan funds are used to buy, build, or substantially improve the home that secures the loan. Interest on HELOC funds used for other purposes (like paying off credit cards or funding a vacation) is not deductible. The combined balance with your first mortgage must stay within the applicable limit.
Sources
Editorial standards
How this page is maintained
USTax Tools updates calculator assumptions and page copy against official source material. We publish for general educational use, not individualized tax advice.
Last reviewed
March 2026
Coverage
2025 mortgage interest deduction
Primary sources
IRS Publication 936
Key Tax Terms
Itemized Deduction
Specific expenses you can deduct instead of taking the standard deduction, including mortgage interest, state/local taxes (up to $10,000), charitable donations, and medical expenses.
Standard Deduction
A fixed dollar amount that reduces your taxable income, available to all filers who do not itemize. For 2025, it is $15,000 for single filers and $30,000 for married filing jointly.
Adjusted Gross Income (AGI)
Your gross income minus specific adjustments such as student loan interest, IRA contributions, and self-employment tax. AGI is the starting point for calculating your taxable income.
Taxable Income
The portion of your income that is actually subject to federal income tax, calculated by subtracting the standard or itemized deduction from your AGI.
Effective Tax Rate
Your total federal income tax divided by your total income, expressed as a percentage. It represents the average rate at which your income is actually taxed.