Form 1040 Schedule A: Filing Your Itemized Deductions

U.S. taxpayers use Form 1040 Schedule A to report itemized deductions. The purpose of this form is to calculate a total deduction that may lower your taxable income more than the standard deduction. Every taxpayer must choose between taking the standard deduction, a fixed dollar amount, or itemizing deductions based on which method yields a larger tax benefit.

Deciding to Itemize Deductions

The choice to itemize requires comparing your potential deductions to the standard deduction. For the 2025 tax year, the standard deduction for Single filers and those Married Filing Separately is $15,150. For Married Filing Jointly couples, the amount is $30,300, and for Head of Household filers, it is $22,750.

These amounts are higher for taxpayers who are age 65 or older or blind. For 2025, an additional $2,000 is available for single and head of household filers, and an extra $1,600 per qualifying individual for joint filers. You must tally your potential itemized deductions to see if the sum is greater than the standard deduction for your filing status. The main categories of expenses include medical bills, state and local taxes, home mortgage interest, and charitable gifts.

For instance, a married couple’s standard deduction is $30,300 for 2025. If they have $12,000 in state and local taxes, $15,000 in mortgage interest, and $4,000 in charitable donations, their total is $31,000. Since this exceeds their standard deduction, itemizing with Schedule A would result in a larger deduction.

Information and Documentation for Each Deduction Category

Medical and Dental Expenses

To deduct medical and dental costs, you must first understand which expenses qualify, including payments for doctor visits, prescription medications, and health insurance premiums paid with after-tax dollars. A rule limits your deduction to the portion of your medical expenses that exceeds 7.5% of your Adjusted Gross Income (AGI). For example, if your AGI is $60,000, the threshold is $4,500, so if you had $6,000 in expenses, you could deduct $1,500.

You will need the total amount of all qualifying medical expenses paid during the year. Keep records like receipts from pharmacies and doctors, and statements from your insurance provider showing any reimbursements, as you can only deduct unreimbursed costs.

State and Local Taxes (SALT)

The deduction for state and local taxes (SALT) allows you to deduct either state and local income taxes or general sales taxes, but not both. You can also include state and local real property taxes and personal property taxes. A limitation caps the total SALT deduction at $10,000 per household annually, or $5,000 if married filing separately.

To determine your deduction, you will need your Form W-2 for state and local income tax withheld. You also need records of any estimated tax payments you made and your property tax bills from your local government.

Home Mortgage Interest and Points

Interest paid on a home mortgage for a loan used to buy, build, or substantially improve your main home or a second home is deductible. The primary document for this deduction is Form 1098, Mortgage Interest Statement, which you receive from your lender. The amount of deductible interest you paid is found in Box 1 of this form. Interest on up to $750,000 of mortgage debt ($375,000 if married filing separately) is deductible.

Investment Interest

This deduction is for interest paid on money you borrowed to purchase investments, such as stocks or bonds. The amount you can deduct is limited to your net investment income for the year. To calculate this deduction, you may need to complete Form 4952, Investment Interest Expense Deduction. The necessary information for this form comes from your brokerage statements, including forms like Form 1099-DIV and Form 1099-INT.

Gifts to Charity

Donations to qualified charitable organizations can be deducted. For cash contributions, you can deduct an amount up to 60% of your AGI. For noncash contributions, such as clothing or household items, the deduction is the fair market value of the items, and they must be in at least “good used condition.”

Documentation requirements depend on the donation amount. For any cash donation under $250, a bank record like a canceled check or credit card statement is sufficient. For any single contribution of $250 or more, you must have a written acknowledgment from the charity. For noncash donations over $500, you must complete and attach Form 8283, Noncash Charitable Contributions, to your return.

Casualty and Theft Losses

The deduction for casualty and theft losses is restricted to personal casualty losses that occurred in a federally declared disaster area. To claim this deduction, you must calculate your loss amount using Form 4684, Casualties and Thefts. You will need the FEMA-assigned disaster declaration number for the event to complete the form correctly.

Completing and Filing Schedule A

The form is organized by deduction category. You will begin with Medical and Dental Expenses. On Line 1, you enter your total unreimbursed medical expenses, and on Line 2, you enter your Adjusted Gross Income (AGI). Lines 3 and 4 are used to calculate your deductible amount after applying the 7.5% AGI threshold.

Next, you will address the State and Local Taxes section. On Line 5a, you will enter either your state and local income taxes or your general sales taxes. Lines 5b and 5c are for your real estate and personal property taxes, and Line 5f applies the $10,000 limitation.

For Home Mortgage Interest, you will enter the amount from your Form 1098 on Line 8a. The lines for investment interest and charitable gifts require you to enter the totals you have already calculated. Cash contributions are entered on Line 11, noncash contributions on Line 12, and a casualty loss from Form 4684 is entered on Line 15.

After filling in all applicable lines, Line 17 is the sum of all your itemized deductions. This final total from Schedule A is then transferred to Line 12 of your Form 1040 or 1040-SR. You must attach the completed Schedule A to your Form 1040 when you file your tax return.