Estimate tax savings from the mortgage interest deduction. Compare standard vs itemized deductions with the $750K/$1M mortgage limit applied.
The mortgage interest deduction is one of the most valuable tax benefits available to homeowners. If you itemize deductions on your federal tax return, you can deduct the interest paid on your mortgage — potentially saving thousands of dollars in taxes each year.
However, the Tax Cuts and Jobs Act of 2017 changed the rules. For mortgages originated after December 15, 2017, the deduction is limited to interest on the first $750,000 of mortgage debt ($375,000 for married filing separately). Mortgages from before that date retain the original $1,000,000 limit.
This calculator estimates your annual interest deduction, compares it against the standard deduction, and shows your actual tax savings. The key question is whether itemizing — with the mortgage deduction plus your other deductions — exceeds the standard deduction. If not, the mortgage interest deduction provides no additional benefit. Running the numbers with this calculator can prevent costly assumptions and help you make housing decisions based on actual tax savings rather than wishful thinking.
Many homeowners assume they benefit from the mortgage interest deduction without checking the math. Since the 2017 tax reform raised the standard deduction significantly, fewer taxpayers actually benefit from itemizing. This calculator shows you whether your mortgage interest plus other deductions exceed the standard deduction — and exactly how much you save if they do.
Annual Interest = approximate first-year interest on balance at the given rate. Deductible Interest = min(Annual Interest, interest on the limit amount). Itemized Total = Deductible Interest + Other Itemized Deductions. Tax Savings = max(0, Itemized Total − Standard Deduction) × Tax Bracket (if itemized > standard) OR Deductible Interest × Tax Bracket (if already itemizing).
Result: $8,400 estimated annual tax savings from mortgage interest
At 7% on $500,000, first-year interest is approximately $35,000. The balance is under the $750K limit, so the full amount is deductible. With $15,000 in other itemized deductions, your itemized total is $50,000 — well above the $29,200 married standard deduction. The mortgage deduction portion saves $35,000 × 24% = $8,400 in federal taxes.
When you file your federal tax return, you choose between the standard deduction and itemized deductions. If you itemize, you list all qualifying deductions — including mortgage interest, state and local taxes (up to $10,000), charitable contributions, and certain other expenses. Your mortgage interest deduction only provides value when your total itemized deductions exceed the standard deduction.
Under the Tax Cuts and Jobs Act, the mortgage debt limit was reduced from $1,000,000 to $750,000 for loans originated after December 15, 2017. If your mortgage exceeds the limit, you can only deduct a proportional share of the interest. For example, if your mortgage is $900,000 and the limit is $750,000, you can deduct 83.3% of the interest paid (750/900).
The mortgage interest deduction provides the greatest benefit in the early years of a large mortgage, when interest payments are highest. It is also more valuable for taxpayers in higher brackets, in high-tax states (where SALT deductions push toward itemizing), and for those with significant charitable giving.
The mortgage interest deduction allows homeowners who itemize their federal tax return to deduct the interest paid on their home mortgage. This reduces taxable income, which lowers the tax owed. It applies to mortgages used to buy, build, or substantially improve your primary or secondary home.
For mortgages taken out after December 15, 2017, the deduction applies to interest on the first $750,000 of mortgage debt ($375,000 if married filing separately). Mortgages originated on or before that date use the previous limit of $1,000,000 ($500,000 MFS). If your balance exceeds the limit, only a proportional share of interest is deductible.
For 2024, the standard deduction is $14,600 for single filers, $29,200 for married filing jointly, and $21,900 for head of household. You only benefit from the mortgage interest deduction if your total itemized deductions exceed these amounts.
Many states allow a mortgage interest deduction on state income tax returns, but rules vary by state. Some states fully conform to federal rules, others have different limits, and some states have no income tax at all. Check your state tax rules for specifics.
Interest on a home equity loan or HELOC is deductible only if the funds were used to buy, build, or substantially improve the home securing the loan. If you used a HELOC for debt consolidation or other non-home purposes, the interest is not deductible under current tax law.
No. The deduction reduces your tax cost, but you are still paying interest. For every $1 of interest, you might save $0.22–$0.37 in taxes (depending on your bracket), meaning you are still out $0.63–$0.78. A smaller mortgage always costs less overall. The deduction is a silver lining, not a reason to borrow more.