Find out how much your mortgage interest actually saves on federal tax. The calculator applies the $750,000 (or $1 million) loan limit, adds points, mortgage insurance, SALT and charity, compares the total with the 2026 standard deduction and computes the real tax difference.
Last updated:
You
$
Mortgage
Interest paid
$
$
Used for the loan limit
$
%
years
$
$
Deductible again from 2026, phased out above $100k AGI
Other itemized deductions
$
Income (or sales) + property tax
$
$
Medical over 7.5% of AGI, etc.
$
$1,650 each if married, $2,050 if single (2026)
%
Estimates state savings if your state allows itemizing
Enter your values to see the result.
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How to use the Mortgage Interest Deduction Calculator
Choose your filing status and enter your adjusted gross income.
Enter the mortgage interest from Form 1098 with your average balance, or let the calculator estimate it from your loan balance, rate and years left.
Pick when the loan was taken out and add any points or mortgage insurance.
Add your other itemized deductions: state and local taxes, charity and others.
Press Calculate deduction to see whether itemizing pays off and how much tax you save.
How the mortgage interest deduction is calculated
Deductible interest = interest paid × (loan limit ÷ average balance), capped at 100%. The limit is $750,000 ($375,000 married filing separately) for loans after December 15, 2017.
Itemized total = deductible interest + points + mortgage insurance + state and local taxes (capped) + charity + other itemized deductions.
Deduction used = the larger of the itemized total and the standard deduction.
Tax saved = tax computed without the mortgage items − tax computed with them.
Example: a married couple with $160,000 AGI paid $22,000 of interest on a $340,000 average balance, $14,000 of state and local taxes and $3,000 to charity. Itemized deductions are $39,000 against a $32,200 standard deduction. Without the mortgage they would take the standard deduction, so the interest only adds $6,800 of extra deduction. In the 22% bracket that saves about $1,496, not the $4,840 that 22% × $22,000 suggests.
Key figures for 2026 returns
Item
Single
Married filing jointly
Head of household
Married filing separately
Standard deduction
$16,100
$32,200
$24,150
$16,100
Mortgage debt limit (after Dec 15, 2017)
$750,000
$750,000
$750,000
$375,000
Mortgage debt limit (older loans)
$1,000,000
$1,000,000
$1,000,000
$500,000
SALT cap (before phase-down)
$40,400
$40,400
$40,400
$20,200
Mortgage insurance phase-out (AGI)
$100,000–$109,000
$100,000–$109,000
$100,000–$109,000
$50,000–$54,500
Figures reflect the One Big Beautiful Bill Act of 2025 and IRS inflation adjustments for 2026. Taxpayers in the 37% bracket have itemized deductions trimmed so they are worth at most 35%; the calculator applies that rule.
Tips
Interest is front-loaded: early in a loan most of each payment is interest, so the deduction is largest in the first years.
"Bunching" charitable gifts into one year can push itemized deductions above the standard deduction in alternate years.
Keep Form 1098 and closing statements; points paid at purchase appear on the settlement statement.
A rent vs buy decision should use the after-tax interest cost shown here, not the full interest.
Frequently asked questions
How much mortgage interest can I deduct?
You can deduct interest on up to $750,000 of mortgage debt used to buy, build or improve your main home and one second home ($375,000 if married filing separately). Loans taken out on or before December 15, 2017 keep the older $1 million limit. If your balance is above the limit, only a proportional share of the interest is deductible.
Is the mortgage interest deduction worth it?
Only if your total itemized deductions are larger than your standard deduction. For 2026 the standard deduction is $16,100 for single filers and $32,200 for married couples filing jointly, so many homeowners with smaller loans get no extra benefit from their mortgage interest.
How much tax does the mortgage interest deduction save?
The saving is the difference between your tax with your best deduction including the mortgage and your tax without it. Only the amount by which itemized deductions exceed the standard deduction saves tax, at your marginal rate. That is why the savings are usually much less than interest × tax rate.
Is PMI tax deductible?
Under the 2025 tax law, mortgage insurance premiums are treated as deductible mortgage interest again starting with 2026 returns. The deduction is reduced by 10% for each $1,000 of AGI over $100,000 ($500 over $50,000 if married filing separately), so it disappears above about $109,000.
Does the SALT cap affect the mortgage interest deduction?
Indirectly. State and local taxes are part of your itemized total, and the cap on them (raised to $40,400 for 2026, phasing down toward $10,000 above $505,000 of income) decides how far above the standard deduction your itemized total goes.
Can I deduct interest on a HELOC or home equity loan?
Yes, but only if the money was used to buy, build or substantially improve the home that secures the loan, and it counts toward the same $750,000 limit. Interest on home equity debt used for other purposes, such as a car or credit cards, is not deductible.
Are mortgage points deductible?
Points paid to buy your main home can usually be deducted in full in the year paid if they meet IRS tests. Points on a refinance are generally deducted over the life of the loan.
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