What the Form Is For

Schedule A (Form 1040 or 1040-SR) is the IRS form you use to claim itemized deductions when filing your federal income tax return. Think of it as an alternative to taking the standard deduction—a choice that could significantly reduce your taxable income if you had substantial qualifying expenses during the tax year.

The form allows you to deduct specific out-of-pocket costs you paid during 2019 in several categories: medical and dental expenses, state and local taxes, home mortgage interest, charitable donations, casualty and theft losses from federally declared disasters, and certain other expenses. By itemizing, you're essentially telling the IRS: "I had these specific expenses that the tax code recognizes as deductible, and I want credit for them instead of taking the flat standard deduction."

For 2019, the standard deduction amounts were $12,200 for single filers, $24,400 for married couples filing jointly, and $18,350 for heads of household. Your decision is straightforward: take the larger of your itemized deductions or your standard deduction. If your qualifying expenses don't exceed these thresholds, itemizing won't benefit you. Schedule A attaches to your main Form 1040 or 1040-SR and feeds directly into line 9 of that form.

When You'd Use It (Late/Amended Filing)

If you're filing your 2019 return after the original deadline—which was July 15, 2020, due to COVID-19 extensions—you can still file Schedule A with your late return. The IRS doesn't prevent you from filing past the deadline; however, penalties and interest may apply if you owed taxes and didn't file or pay on time.

More importantly, if you already filed your 2019 return and took the standard deduction but later realized you would have saved more by itemizing, you can amend your return using Form 1040-X (Amended U.S. Individual Income Tax Return). You generally have three years from the original filing deadline to amend and claim a refund. For 2019 returns, this means you typically have until April 15, 2023, to file an amended return, though extensions may apply in certain circumstances.

Two specific situations highlighted in the 2019 instructions make amending particularly relevant: First, legislation retroactively extended the mortgage insurance premiums deduction to 2019. If you were eligible but didn't claim it on your original return, you need to file Form 1040-X. Second, the temporary increase in limitations on "qualified contributions" (donations for college athletic seating rights) was also extended retroactively to 2019. If either applies to you, amending your 2019 return could put money back in your pocket.

When amending, you'll attach a new Schedule A showing your corrected itemized deductions and explain the changes in the designated section of Form 1040-X. The IRS will process your amended return separately from original filings, which typically takes longer—often 16 weeks or more.

Key Rules for 2019

Several critical rules governed Schedule A for tax year 2019, many stemming from the Tax Cuts and Jobs Act (TCJA) that took effect in 2018:

The $10,000 SALT Cap: Perhaps the most significant limitation is the $10,000 cap ($5,000 if married filing separately) on state and local taxes (SALT). This includes the total of state and local income taxes (or general sales taxes if you elect that option instead), real estate taxes, and personal property taxes. Even if you paid $30,000 in property taxes and $15,000 in state income taxes, you can only deduct $10,000 combined on line 5e.

Medical Expense Threshold: You can only deduct medical and dental expenses exceeding 7.5% of your adjusted gross income (AGI). If your AGI was $60,000, you must subtract $4,500 (7.5% of $60,000) from your total medical expenses before claiming any deduction. This threshold means only taxpayers with substantial medical costs benefit from this deduction.

Mortgage Interest Limitations: For mortgages taken out after December 15, 2017, you can deduct interest on up to $750,000 of qualified home acquisition debt ($375,000 if married filing separately). For mortgages existing before that date, the old $1 million limit still applies. Home equity loan interest is generally only deductible if you used the loan proceeds to buy, build, or substantially improve your home.

Mortgage Insurance Premiums: Thanks to retroactive legislation, you could deduct qualified mortgage insurance premiums paid in 2019, subject to income phaseouts beginning at $100,000 AGI ($50,000 if married filing separately).

Charitable Contribution Limits: Generally, you can deduct cash contributions up to 60% of your AGI, with different limits for appreciated property and other contribution types. Documentation requirements are strict—you need written acknowledgment from charities for any single donation of $250 or more.

Standard Mileage Rates: For 2019, the IRS allowed 20 cents per mile for medical-related driving and 14 cents per mile for charitable volunteer work.

No Miscellaneous Deductions: The TCJA suspended miscellaneous itemized deductions (like unreimbursed employee expenses, tax preparation fees, and investment expenses) for tax years 2018–2025. These can't be claimed on 2019 returns.

Step-by-Step Guide (High Level)

Step 1 - Gather Your Records

Before touching the form, collect all documentation: medical bills and insurance statements, property tax bills, Form 1098 (Mortgage Interest Statement), charitable donation receipts, and state/local tax payment records.

Step 2 - Medical and Dental Expenses (Lines 1-4)

Add up all unreimbursed medical and dental expenses for yourself, your spouse, and dependents. Include insurance premiums (unless paid pre-tax through your employer), doctor visits, prescriptions, dental work, eyeglasses, and qualified long-term care insurance. Calculate 7.5% of your AGI (from Form 1040, line 8b), then subtract that amount from your total medical expenses. Enter the result on line 4.

Step 3 - Taxes You Paid (Lines 5-7)

Choose whether to deduct state and local income taxes OR general sales taxes on line 5a—you can't deduct both. Most taxpayers choose income taxes. Add your real estate taxes (line 5b) and personal property taxes (line 5c). Total these on line 5d, but enter only up to $10,000 ($5,000 if married filing separately) on line 5e. Add any other deductible taxes on line 6, then total lines 5e and 6 on line 7.

Step 4 - Interest You Paid (Lines 8-10)

Enter home mortgage interest from Form(s) 1098 on line 8a. If you paid mortgage interest not reported on Form 1098 (such as to an individual), enter it on line 8b with required identifying information. Include deductible points on line 8c and mortgage insurance premiums on line 8d. Total these on line 8e. If you have investment interest expense, you'll need Form 4952; enter the allowable amount on line 9. Add lines 8e and 9 for line 10.

Step 5 - Charitable Gifts (Lines 11-14)

Separate your donations into cash contributions (line 11) and non-cash contributions (line 12). For non-cash donations over $500, you must attach Form 8283. If you're carrying over charitable contributions from prior years due to AGI limitations, enter that on line 13. Total lines 11-13 on line 14.

Step 6 - Casualty and Theft Losses (Line 15)

Only losses from federally declared disasters are deductible. If applicable, complete Form 4684 and transfer the amount to Schedule A, line 15.

Step 7 - Other Itemized Deductions (Line 16)

List any other deductible items specified in the instructions, such as gambling losses (to the extent of gambling winnings) or federal estate tax on income in respect of a decedent.

Step 8 - Calculate Total (Line 17)

Add lines 4, 7, 10, 14, 15, and 16. This is your total itemized deductions. Transfer this amount to Form 1040 or 1040-SR, line 9.

Common Mistakes and How to Avoid Them

Mistake #1 - Including Non-Deductible Medical Expenses

Many taxpayers include cosmetic surgery (unless medically necessary), over-the-counter medications (except insulin), funeral costs, or health club memberships. Avoid this by carefully reviewing IRS Publication 502, which lists exactly what qualifies. When in doubt, it probably doesn't count.

Mistake #2 - Exceeding the SALT Cap Without Realizing It

Taxpayers in high-tax states often pay far more than $10,000 in state and local taxes but mistakenly enter their full amount on line 5e. Avoid this by carefully reading line 5e's instruction to "Enter the smaller of line 5d or $10,000." Always apply this cap.

Mistake #3 - Deducting Both Income and Sales Taxes

Line 5a clearly states you must choose either state and local income taxes OR general sales taxes—not both. Some taxpayers check the sales tax box but enter income tax amounts. Avoid this by making a deliberate choice (most people benefit from income taxes) and checking only the appropriate box if claiming sales taxes.

Mistake #4 - Missing Documentation Requirements for Charitable Gifts

The IRS can disallow deductions without proper documentation. For donations of $250 or more, you need written acknowledgment from the charity before filing. For non-cash donations over $500, Form 8283 is required. Avoid this by requesting written receipts at the time of donation and maintaining a donation log throughout the year.

Mistake #5 - Deducting Reimbursed Medical Expenses

If your insurance company paid for a medical expense, or if you paid it with pre-tax dollars from a health savings account or flexible spending account, you can't deduct it. Avoid this by reducing your medical expense total by all reimbursements received in 2019, even if they reimbursed prior-year expenses.

Mistake #6 - Forgetting to Compare to Standard Deduction

Some taxpayers automatically itemize because they always have, even when their itemized total is less than the standard deduction. Avoid this by calculating both amounts. Software usually does this automatically, but if preparing by hand, always verify that itemizing actually saves you money.

Mistake #7 - Deducting Prepaid 2020 Taxes in 2019

Some taxpayers paid their 2020 property taxes early in December 2019 hoping to deduct them. However, for 2019, only taxes assessed prior to 2020 are deductible. Avoid this by understanding that you can only deduct taxes that were assessed in 2019, regardless of when you paid them.

What Happens After You File

Initial Processing

The IRS will process your return, typically within 21 days if you filed electronically. The agency's computers will check mathematical accuracy and verify that your itemized deductions don't contain obvious errors. Your AGI and total itemized deductions will be matched against W-2s, 1099s, and other information documents the IRS receives.

Refund or Payment

If you're owed a refund, it will be issued once processing is complete—usually within 21 days for e-filed returns, longer for paper returns. If you owe additional tax, your payment is due by the filing deadline regardless of when you actually file.

Document Retention

You should keep Schedule A and all supporting documentation for at least three years from the filing date. The IRS can generally audit returns within three years of filing, though this extends to six years if you substantially understated income. Keep mortgage interest statements, property tax bills, medical receipts, and charitable donation acknowledgments in an organized file.

Potential for Additional Review

Returns with itemized deductions, particularly large ones relative to income, may face additional scrutiny. The IRS uses algorithms to identify returns for examination. Common triggers include: unusually large charitable deductions (especially non-cash), substantial medical expenses, significant casualty losses, or patterns inconsistent with your income level. This doesn't mean you shouldn't claim legitimate deductions—just ensure you have solid documentation.

Correspondence or Audit

If the IRS has questions, you'll receive correspondence by mail (never by phone or email). They might ask for documentation of specific deductions. In a full audit, they'll examine your entire return. Respond promptly to any IRS letters and provide requested documentation. If you can't substantiate a deduction, the IRS will disallow it, assess additional tax, and charge interest and possibly penalties.

State Returns

Your federal Schedule A may affect your state return, as many states use federal AGI as a starting point. Some states allow different deductions than the federal government, so file your state return carefully.

FAQs

Q1: Can I itemize if my spouse takes the standard deduction?

No. If you're married filing jointly, you both must either itemize or take the standard deduction—you can't mix and match. If you're married filing separately and one spouse itemizes, the other spouse must itemize as well, even if the standard deduction would be better. This rule prevents couples from getting the benefit of both methods.

Q2: What if I forgot to itemize but should have?

You can amend your return using Form 1040-X. You generally have three years from the original filing deadline to amend and claim a refund. Attach a completed Schedule A showing your itemized deductions and explain the change in Part III of Form 1040-X. The IRS will process the amendment and issue any additional refund due, though amended returns take considerably longer to process than original returns.

Q3: Can I deduct medical expenses I paid for my elderly parent?

Yes, if you provided more than half their support, even if you can't claim them as a dependent because their income exceeds the threshold. You can also deduct medical expenses for someone who would have been your dependent except that they filed a joint return or had gross income over $4,200. The key is the support test and relationship requirements outlined in IRS Publication 502.

Q4: How do I choose between deducting state income taxes or sales taxes?

Most taxpayers benefit from deducting state income taxes, but residents of states with no income tax (like Florida, Texas, or Washington) should choose sales taxes. You can also choose sales taxes if you made major purchases (vehicle, boat, home improvements) and can document the sales tax paid. The IRS provides optional sales tax tables to simplify the calculation if you don't have actual receipts. Remember, you're still subject to the $10,000 overall SALT cap regardless of which you choose.

Q5: Are home equity loan interest payments deductible?

It depends on how you used the money. If you used home equity loan proceeds to buy, build, or substantially improve your home, the interest is deductible (subject to the mortgage debt limits). However, if you used the loan to pay off credit cards, buy a car, or fund a vacation, the interest isn't deductible under current law. This is a significant change from prior years when home equity interest was deductible regardless of use.

Q6: What documentation do I need to keep for charitable deductions?

For cash donations under $250, you need a bank record or written communication from the charity. For any single donation of $250 or more, you must have a written acknowledgment from the charity that includes the amount, whether you received anything in return, and a description and good-faith estimate of any goods or services provided. For non-cash donations over $500, file Form 8283. For non-cash donations over $5,000, you generally need a qualified appraisal. Never staple receipts to your return—keep them in your files in case of audit.

Q7: Can I deduct health insurance premiums?

It depends on your situation. If you're self-employed, you should claim health insurance premiums as an adjustment to income on Schedule 1 (Form 1040), line 16—this is more advantageous than itemizing because it reduces AGI. If you're an employee and pay premiums with after-tax dollars (not through a cafeteria plan), you can include them in medical expenses on Schedule A, subject to the 7.5% AGI threshold. You can't deduct premiums paid through pre-tax payroll deductions because those amounts are already excluded from your taxable income.

Sources

Sources: All information in this guide comes from official IRS publications for tax year 2019: Schedule A (Form 1040) 2019, 2019 Instructions for Schedule A, and About Schedule A (Form 1040).