The mortgage interest deduction reduces your taxable income, not your refund directly
The amount you can deduct for mortgage interest depends on how much interest you actually paid during the year, not on a fixed percentage or formula. Your mortgage lender sends you a Form 1098 in January showing the interest you paid in the previous year. You use that number to reduce your taxable income when you file your return. A smaller taxable income can result in a larger refund if you're owed one, but the deduction itself is not a refund—it's a reduction in the income the IRS taxes.
The key limit is the loan principal cap: you can only deduct interest on mortgage debt up to $750,000 (or $375,000 if you're married filing separately). If your mortgage is larger than that, you can deduct interest only on the first $750,000 of the loan. This cap applies to mortgages taken out after December 15, 2017. Mortgages from before that date have a $1 million cap instead.
You must also itemize deductions on your tax return to claim the mortgage interest deduction. Most people take the standard deduction instead, which means they don't list individual deductions at all. For 2024, the standard deduction is $14,600 for single filers and $29,200 for married couples filing jointly. If your mortgage interest plus other deductible expenses (property taxes, charitable donations, medical expenses) add up to more than the standard deduction, itemizing will save you more in taxes.
Key Takeaways
- Your mortgage lender reports the interest you paid on Form 1098, which you use to calculate your deduction—not a refund amount.
- You can only deduct interest on the first $750,000 of mortgage principal (or $1 million if the loan originated before December 16, 2017).
- You must itemize deductions on your tax return to claim mortgage interest; most taxpayers use the standard deduction instead and receive no benefit from mortgage interest.
- The actual tax savings depend on your tax bracket—a person in the 22% bracket saves $0.22 in taxes for every dollar of deductible interest, while someone in the 12% bracket saves $0.12.
How to find the interest amount on your Form 1098
Your lender mails Form 1098 (Mortgage Interest Statement) by January 31 each year. Box 1 shows the total mortgage interest you paid during that tax year. This is the number you need. If you made extra payments or paid off your mortgage early, the interest shown reflects only what you actually paid, not what you would have paid over the full loan term.
If you don't receive a Form 1098 by early February, contact your lender directly. Some lenders allow you to view it online through your account portal. If the form shows an incorrect amount, ask your lender to issue a corrected one (Form 1098-C). Do not estimate or use last year's amount—the IRS matches the Form 1098 your lender files with your tax return.
If you paid off your mortgage during the year, you'll receive a Form 1098 showing only the interest paid before the payoff date. If you refinanced, you may receive two forms—one from your original lender and one from the new lender—because you paid interest to both during that year.
When itemizing deductions makes sense
Itemizing is worth doing only if your total deductible expenses exceed the standard deduction. For 2024, that threshold is $14,600 (single) or $29,200 (married filing jointly). Your deductible expenses include mortgage interest, state and local property taxes (capped at $10,000), charitable donations, and certain medical expenses.
Example: A married couple with $8,000 in mortgage interest, $6,000 in property taxes, and $2,000 in charitable donations has $16,000 in itemized deductions. Since $16,000 exceeds the $29,200 standard deduction, they would not benefit from itemizing—they'd use the standard deduction instead. But if the same couple had $12,000 in mortgage interest, $10,000 in property taxes, and $8,000 in charitable donations, their total would be $30,000, which exceeds $29,200, so itemizing would save them money.
Use IRS Form 1040 Schedule A to itemize. You list mortgage interest in line 8a, along with your Form 1098 box number. If you're unsure whether itemizing or taking the standard deduction will save you more, calculate both and use whichever is larger.
How the deduction affects your refund or tax bill
The mortgage interest deduction reduces your taxable income, which can lower the tax you owe or increase the refund you receive. The actual dollar impact depends on your tax bracket. If you're in the 22% federal tax bracket, a $10,000 mortgage interest deduction saves you $2,200 in federal income tax. If you're in the 12% bracket, the same deduction saves you $1,200.
Your tax bracket is determined by your total income for the year. The IRS publishes new brackets annually. For 2024, the 12% bracket covers income up to roughly $23,200 (single) or $46,400 (married filing jointly). The 22% bracket covers income from roughly $23,200 to $94,300 (single) or $46,400 to $189,750 (married filing jointly). Higher income means a higher bracket and a larger tax savings from the deduction.
If you're expecting a refund, the mortgage interest deduction is one factor among many that determines the size of that refund. Your refund is based on the total tax you owe minus the total tax already withheld from your paychecks or paid through estimated tax payments. The deduction lowers the tax you owe, which can increase your refund if you've had enough withheld.
Mortgages that don't may have access to for the deduction
Not all mortgage debt qualifies. You can deduct interest only on a loan used to buy, build, or improve your home. Interest on a home equity line of credit (HELOC) or second mortgage used for home improvements also qualifies, but only up to the $750,000 principal cap combined with your primary mortgage.
If you took out a HELOC or second mortgage for purposes other than home improvement—such as paying off credit cards, funding a business, or paying medical bills—the interest on that loan is not deductible, even if the loan is secured by your home. The IRS looks at what the money was used for, not what collateral backs the loan.
Interest on a mortgage used to buy a second home or investment property may be deductible under the same rules, but the loan must be secured by that property. Consult a tax professional if you own multiple properties or used a home equity loan for mixed purposes.
State and local tax considerations
Some states and cities allow an additional deduction for mortgage interest on your state or local tax return, separate from the federal deduction. A few states—including New York and California—have their own mortgage interest deduction rules that may differ from federal rules. If you live in a state with an income tax, check your state's tax authority website or consult a tax professional to see whether you can claim mortgage interest on your state return as well.
The federal $10,000 cap on state and local taxes (SALT) does not directly limit your mortgage interest deduction, but it does limit the total of all state and local taxes you can deduct federally. If your property taxes alone exceed $10,000, you cannot deduct any state income tax, which may affect your overall itemization strategy.
Frequently Asked Questions
Can I deduct mortgage interest if I take the standard deduction?
No. The mortgage interest deduction is only available if you itemize deductions on Schedule A. If you take the standard deduction, you cannot claim mortgage interest or any other itemized deductions. Most taxpayers use the standard deduction because it's larger than their total itemized deductions would be.
What if I paid off my mortgage early—can I deduct interest I didn't pay?
No. You can only deduct interest you actually paid during the tax year. If you paid off your mortgage in June, you deduct only the interest paid from January through June. You cannot deduct interest on the remaining balance that you would have paid if you had kept the loan.
Do I need to keep my Form 1098 to claim the deduction?
You should keep it for your records, but you don't need to mail it to the IRS. The IRS receives a copy directly from your lender. However, if the IRS questions your return, you'll need the Form 1098 to prove the amount you deducted.
Can I deduct mortgage interest on a rental property?
Yes, but it's reported differently. Mortgage interest on a rental property is deducted on Schedule E (Supplemental Income and Loss), not on Schedule A. It's treated as a business expense, not an itemized personal deduction, so you can claim it regardless of whether you itemize.
What if my lender reports the wrong amount on Form 1098?
Contact your lender when ready and ask them to issue a corrected Form 1098-C. Do not file your tax return with an incorrect amount. The IRS will match the Form 1098 your lender files with the amount you report, and a mismatch can trigger an audit notice.