Where to Report Mortgage Interest on 1040: Schedule A Lines 8a–8c

Mortgage interest is reported on Schedule A (Form 1040), the itemized deductions schedule. Interest shown on a Form 1098 from your lender goes on Line 8a. Interest paid to a private lender who did not issue a 1098 goes on Line 8b. Deductible points that were not reported on a 1098 go on Line 8c. The total from Schedule A (Line 17) then transfers to Line 12e of Form 1040, where it replaces the standard deduction.¹

Start With Form 1098

Your lender sends Form 1098 (Mortgage Interest Statement) by January 31 following the tax year. Lenders are required to issue one if they received at least $600 in mortgage interest from you during the year.² If you refinanced mid-year, expect two forms from two servicers.

Three boxes drive what you enter on Schedule A:

Box 1 is the total mortgage interest the lender received from you during the year. This is the primary figure. It does not include points.²
Box 2 shows the outstanding mortgage principal as of January 1 (or the acquisition date for a new loan). Use it to check whether your balance is within the debt limits for full deductibility.³
Box 6 shows points paid on the purchase of a principal residence. Points on second homes, investment properties, and refinances are not shown here even when some remain deductible.³

Cross-check Box 1 against your own payment records before you enter anything. Extra principal payments should not appear in Box 1, and discrepancies can trigger an IRS notice.

The Schedule A Lines

Schedule A collects all itemized deductions. The mortgage interest block uses three lines.¹

Line 8a — Interest Reported on Form 1098

Enter the interest and points reported to you on Form 1098. If you received more than one 1098 during the year, combine the totals on this line. If a debt limit applies to you because your total mortgage balance exceeds the threshold that matches your origination date, calculate the deductible portion first using the worksheet in IRS Publication 936, and put that reduced figure on Line 8a rather than the raw Box 1 number.⁴

Line 8b — Interest Paid to a Private Lender

If you paid mortgage interest to an individual (a seller-financed purchase, for example) who did not issue a Form 1098, enter that interest on Line 8b. You must also write the recipient’s name, address, and Social Security number on the dotted lines next to Line 8b. Skip this step and the deduction can be disallowed.¹

Line 8c — Points Not Reported on Form 1098

Line 8c is for deductible points that don’t appear on any 1098 you received. The most common case is amortized points from a refinance. Points on a refinanced mortgage aren’t deducted all at once; you spread them evenly over the life of the new loan.⁵ A $3,000 charge on a 30-year refinance produces a $100 deduction each year on Line 8c. If you refinance again or pay the loan off early, any remaining unamortized points come off in that final year.

Points paid to buy a principal residence work differently. They generally deduct in full in the year you pay them and typically show up in Box 6 of your 1098, which means they ride along with Line 8a rather than sitting on Line 8c.⁵ Seller-paid points can still be deducted by the buyer, though you have to reduce your home’s cost basis by the same amount, which may affect the gain calculation when you sell.

Moving the Total to Form 1040

Once the mortgage interest lines are complete, they combine with your other itemized deductions (state and local taxes, charitable contributions, qualifying medical expenses) to produce the total on Line 17 of Schedule A. That Line 17 total flows to Line 12e of Form 1040, the same line where a non-itemizer would enter the standard deduction.⁶ The deduction reduces taxable income; it does not change your adjusted gross income, which is already fixed on Line 11 before deductions come into play.⁷

You Have to Itemize to Use These Lines

Schedule A only helps you if your total itemized deductions exceed the standard deduction for your filing status. For 2026, the standard deduction is $16,100 for single filers and those married filing separately, $32,200 for married filing jointly, and $24,150 for head of household.⁸ If your mortgage interest plus your other qualifying deductions comes in under those numbers, the standard deduction wins and Schedule A stays blank. Recheck this comparison every year, because your mortgage balance shrinks and so does the interest you pay.

One trap for married couples filing separately: if your spouse itemizes, you must also itemize, even when the standard deduction would be larger for you.⁷

Adjust for the Debt Limit Before You Enter Box 1

The amount of mortgage debt eligible for the interest deduction depends on when the loan originated. Loans taken out after December 15, 2017 support interest deduction on up to $750,000 of acquisition debt ($375,000 if married filing separately). Loans from October 14, 1987 through December 15, 2017 use a $1,000,000 limit ($500,000 if married filing separately). Older debt is grandfathered and fully deductible.⁹ The limits apply to the combined debt on your main home and second home, not to each property separately.

If your average balance is under the limit that applies to you, put the Box 1 figure straight on Line 8a. If it exceeds the limit, run the Table 1 worksheet in Publication 936 first; the deductible share is your qualified loan limit divided by your average total mortgage balance, applied to total interest paid.⁴

What Does Not Belong on These Lines

Several items show up on mortgage statements or on Form 1098 itself but do not go on Lines 8a through 8c:

Mortgage insurance premiums. The itemized deduction for PMI has expired. Your 1098 may still report the amount, but you cannot deduct it.⁴
Homeowner’s insurance and escrowed property taxes. Property taxes go on the SALT lines of Schedule A, not the interest lines. Homeowner’s insurance on a personal residence is not deductible at all.
Home equity loan or HELOC interest where the proceeds were not used to buy, build, or substantially improve the home securing the loan. Interest on a HELOC used to pay credit cards, buy a car, or take a vacation is not deductible.¹⁰
Interest on a third home. The deduction covers your main home and one designated second home only.
Rental property mortgage interest. If you rent out the property rather than living in it, the interest is a rental expense on Schedule E, not a Schedule A itemized deduction.¹⁰

For a cash-out refinance, the portion of the new loan that replaced the old balance keeps its original character, and the extra cash-out portion only qualifies for Schedule A treatment if you used the proceeds to buy, build, or substantially improve the home that secures the loan.⁴ Cash-out used for business or investment activity is deducted under separate rules and does not belong on Schedule A at all.

1
Internal Revenue Service. Instructions for Schedule A (Form 1040) (2025)
2
Internal Revenue Service. Form 1098 Mortgage Interest Statement
3
Internal Revenue Service. Instructions for Form 1098 (12/2026)
4
Internal Revenue Service. Publication 936 (2025), Home Mortgage Interest Deduction
5
Internal Revenue Service. Topic No. 504, Home Mortgage Points
6
IRS. Schedule A (Form 1040) 2025
7
Internal Revenue Service. Instructions for Form 1040 and 1040-SR
8
Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026, Including Amendments From the One, Big, Beautiful Bill
9
Office of the Law Revision Counsel. 26 USC 163 – Interest
10
Internal Revenue Service. Topic No. 505, Interest Expense