What the Form Is For

Schedule A (Form 1040) is the IRS form you use to claim itemized deductions—specific expenses you can subtract from your income to reduce your tax bill. Think of it as an alternative to the standard deduction, which is a fixed dollar amount everyone can claim based on their filing status.

When you itemize on Schedule A, you're essentially telling the IRS: ""Instead of taking the standard deduction, I want to add up all my qualifying expenses and deduct those instead."" The form covers six main categories of deductible expenses: medical and dental costs, taxes you paid (state, local, and real estate), interest you paid (primarily mortgage interest), charitable donations, casualty and theft losses, and certain other miscellaneous deductions.

You'll only benefit from using Schedule A if your total itemized deductions exceed your standard deduction. For 2020, the standard deduction amounts were $12,400 for single filers, $24,800 for married couples filing jointly, and $18,650 for heads of household. If you're 65 or older, you get an additional $1,300 ($1,650 if unmarried). Schedule A attaches to your main Form 1040 and must be filed alongside your regular tax return.

IRS.gov - About Schedule A

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

You typically file Schedule A at the same time you file your original tax return—by April 15, 2021, for the 2020 tax year (or October 15, 2021, if you filed for an extension). However, life happens, and you might discover later that itemizing would have saved you money.

If you already filed your 2020 return using the standard deduction and later realize you should have itemized instead, you can file an amended return using Form 1040-X. The IRS generally allows you three years from the original filing deadline to amend your return. For 2020 returns, that meant you had until April 15, 2024, to file an amended return claiming itemized deductions instead of the standard deduction.

Common reasons people file amended returns with Schedule A include: discovering they forgot to claim significant medical expenses, receiving corrected mortgage interest statements (Form 1098), finding documentation for charitable contributions they'd forgotten about, or realizing their property taxes and state taxes combined exceeded the $10,000 cap and they miscalculated initially. The IRS automatically corrects simple math errors, so you don't need to amend for those. However, if you reported incorrect amounts or forgot entire categories of deductions, an amended return with a completed Schedule A is necessary.

IRS.gov - Topic No. 308, Amended Returns

Key Rules for 2020

$10,000 SALT Cap

Several important rules governed Schedule A for tax year 2020. First and foremost: the $10,000 cap on state and local taxes (often called the SALT cap). This limit, which applied to married couples filing jointly and single filers alike ($5,000 for married filing separately), meant you could only deduct up to $10,000 total from line 5, which includes state and local income taxes, real estate taxes, and personal property taxes combined.

Medical and Dental Expenses

For medical and dental expenses, you could only deduct amounts exceeding 7.5% of your adjusted gross income (AGI). If your AGI was $60,000, only medical expenses above $4,500 were deductible. You had to track unreimbursed expenses like doctor visits, prescription medications, health insurance premiums (not paid pre-tax through your employer), medical equipment, and mileage at 17 cents per mile for medical travel.

Home Mortgage Interest

Home mortgage interest was deductible on loan balances up to $750,000 ($375,000 if married filing separately) for mortgages taken out after December 15, 2017. For older mortgages, the limit was $1 million. Importantly, the interest had to be on debt used to buy, build, or substantially improve your home—not for refinancing to pay off credit cards or other personal expenses.

Charitable Contributions

Charitable contributions had enhanced rules for 2020: cash donations could potentially be deducted up to 100% of your AGI (up from the usual 60%) if you elected a special temporary suspension of limitations. You needed written acknowledgment for any single donation of $250 or more, and donated goods required receipts and fair market value documentation.

Recordkeeping Requirements

Finally, recordkeeping was crucial. The IRS required you to maintain receipts, canceled checks, bank statements, and acknowledgment letters to substantiate every deduction claimed. Electronic records were acceptable, but you needed to keep everything for at least three years after filing.

IRS.gov - 2020 Instructions for Schedule A

Step-by-Step: How to Complete Schedule A (High Level)

Step 1: Gather your documentation.

Before you start filling out the form, collect all relevant documents: medical bills and insurance statements, mortgage interest statements (Form 1098), property tax bills, state and local tax records (W-2s show withholding), and charitable contribution receipts.

Step 2: Calculate medical and dental expenses (Lines 1-4).

Add up all unreimbursed medical and dental expenses for yourself, your spouse, and dependents. Multiply your AGI (from Form 1040, line 11) by 7.5%. Subtract this amount from your total medical expenses—only the amount above this threshold is deductible. Enter this on line 4.

Step 3: Total your taxes paid (Lines 5a-5d).

On line 5a, enter either your state and local income taxes OR general sales taxes (you can't claim both—use whichever is higher). On line 5b, enter real estate taxes. On line 5c, enter personal property taxes (like car registration fees based on vehicle value). Add these up, but remember the $10,000 maximum for line 5d.

Step 4: Report interest paid (Lines 8a-8e).

Enter your home mortgage interest from Form 1098 on line 8a. If applicable, add mortgage insurance premiums on line 8d and investment interest on line 8e. Total these on line 8e.

Step 5: Calculate gifts to charity (Lines 11-14).

Separate cash donations from non-cash donations. Cash gifts go on line 11, and donated property goes on line 12. Add these for your total charitable contributions on line 14.

Step 6: Add other deductions (Lines 16-17).

If you have casualty or theft losses from a federally declared disaster or other qualifying deductions, include them here.

Step 7: Calculate your total itemized deductions (Line 17).

Add up all your deduction categories. This is the number that will transfer to Form 1040, line 12, if it exceeds your standard deduction. If your standard deduction is higher, don't file Schedule A—just take the standard deduction instead.

IRS.gov - Schedule A Form and Instructions

Common Mistakes and How to Avoid Them

Mistake #1: Claiming the standard deduction AND itemizing.

You must choose one or the other—you can't do both. Before completing Schedule A, compare your total itemized deductions to your standard deduction amount and use whichever is higher. Tax software usually does this automatically, but manual filers sometimes forget.

Mistake #2: Forgetting the 7.5% AGI floor for medical expenses.

Many taxpayers incorrectly deduct all medical expenses without realizing only the amount exceeding 7.5% of AGI qualifies. If your AGI was $50,000 and you had $5,000 in medical expenses, only $1,250 is deductible ($5,000 minus $3,750). Always calculate this threshold first.

Mistake #3: Exceeding the $10,000 SALT cap.

Taxpayers in high-tax states often add up all their state income taxes, property taxes, and other local taxes, only to enter the full amount on Schedule A. Remember, the total for lines 5a through 5c is capped at $10,000 ($5,000 if married filing separately)—even if you paid $25,000, you can only deduct $10,000.

Mistake #4: Deducting non-qualified mortgage interest.

Interest on home equity loans or cash-out refinances used for purposes other than buying, building, or substantially improving your home isn't deductible. Make sure your mortgage interest deduction reflects only qualifying debt. Check what you used the loan proceeds for, not just what your Form 1098 shows.

Mistake #5: Inadequate charitable contribution documentation.

The IRS requires written acknowledgment from the charity for any single contribution of $250 or more. Your canceled check isn't enough. For non-cash donations over $500, you need to file Form 8283. Keep donation receipts and written thank-you letters from organizations.

Mistake #6: Including non-deductible taxes.

Federal income tax, Social Security tax, Medicare tax, and HOA fees are NOT deductible on Schedule A. Only state and local income taxes (or sales taxes), real estate taxes on property you own, and certain personal property taxes qualify.

How to avoid these mistakes: Use reputable tax software that asks questions and calculates automatically, or work with a qualified tax professional. Keep meticulous records throughout the year in organized folders (physical or digital). Read the Schedule A instructions carefully before filling out the form. When in doubt about whether something is deductible, consult IRS Publication 17 or IRS.gov rather than guessing.

What Happens After You File

Once you submit your 2020 tax return with Schedule A attached, the IRS processes it through both automated systems and human review. Most returns are processed within 21 days if filed electronically, though paper returns take 6-8 weeks or longer.

Initial processing

The IRS computers first check for math errors, missing forms, and obvious inconsistencies. They'll automatically correct simple arithmetic mistakes and may send you a notice (CP2000) if your deductions don't match information from third parties (like your mortgage interest not matching what your lender reported). These aren't audits—they're automated matching programs.

Audit selection

A small percentage of returns with Schedule A get selected for audit. Certain red flags increase your odds: extremely high deductions relative to income, round numbers throughout (suggesting estimates rather than actual expenses), large charitable contributions, and significant deviations from statistical norms for your income level. If selected, you'll receive a letter in the mail (the IRS never initiates contact by phone or email).

Types of audits

If you're audited, it will be either a correspondence audit (done by mail, where the IRS requests documentation for specific items), an office audit (you bring records to an IRS office), or a field audit (an IRS agent visits your home or business—rare for individual returns). Most Schedule A audits are correspondence audits focusing on substantiation of medical expenses, charitable donations, or tax payments.

Your refund or payment

If you're owed a refund, direct deposit typically arrives within 21 days of electronic filing. If you owe taxes, your payment is due by the April 15 deadline regardless of when you file. Schedule A doesn't delay refund processing unless your return is selected for review. You can track your refund status using the ""Where's My Refund?"" tool at IRS.gov.

Record retention

Keep your completed Schedule A, all supporting documentation, and copies of your entire tax return for at least three years from the filing date. If the IRS audits you, you'll need these records to prove your deductions. For substantial omissions of income (25% or more), the IRS has six years to audit; for fraud, there's no time limit.

IRS.gov - IRS Audits

Frequently Asked Questions (FAQs)

Q1: How do I know if I should itemize or take the standard deduction?

A: Add up all your potential Schedule A deductions before deciding. Only itemize if your total exceeds your standard deduction ($12,400 single, $24,800 married filing jointly, $18,650 head of household for 2020). Common candidates for itemizing include homeowners with large mortgages, people with significant medical expenses, those living in high-tax states, and regular charitable donors. If you're close to the threshold, tax software can run the calculation both ways to show which saves more money.

Q2: Can I deduct medical expenses paid for my adult children?

A: Yes, but only if they qualify as your dependent. You can deduct medical expenses paid for anyone who was your dependent either when services were provided or when you paid for them. Even if your child earned $4,300 or more (disqualifying them as a dependent for other purposes), you can still deduct medical expenses you paid for them if you provided more than half their support. Adult children under 27 covered by your health insurance may present special rules—see IRS Publication 502 for details.

Q3: What if I forgot to itemize and took the standard deduction instead?

A: You can file an amended return (Form 1040-X) to switch from the standard deduction to itemized deductions, but only within three years of your original filing deadline. For 2020 returns, the deadline to amend was April 15, 2024. Calculate whether the additional refund justifies the effort—amending requires gathering all documentation, completing Schedule A, and waiting several months for the IRS to process the amendment. The IRS won't automatically suggest you itemize if you took the standard deduction incorrectly.

Q4: Are HOA fees or home insurance premiums deductible on Schedule A?

A: No. Homeowners association fees, homeowners insurance premiums, mortgage principal payments, and utilities are not deductible on Schedule A for your primary residence. Only mortgage interest (line 8a) and real estate taxes (line 5b) qualify. However, if you use part of your home for business, you might deduct a portion of these expenses on Schedule C. Don't confuse homeowners insurance with mortgage insurance premiums (PMI), which were deductible on line 8d for 2020 if your AGI was below certain thresholds.

Q5: Can I deduct property taxes paid at closing when I bought a house?

A: Yes, but with limitations. The property taxes you paid at closing (shown on your settlement statement) are deductible on Schedule A, line 5b. However, remember the $10,000 combined cap for all state, local, and property taxes. Any amounts the seller paid are not deductible by you—only the portion you actually paid counts. Also, don't confuse property taxes with other settlement charges like recording fees, title insurance, or attorney fees, which aren't deductible (though they may increase your home's cost basis for future capital gains calculations).

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

A: It depends on the donation amount. For cash donations under $250, keep bank records or written communication from the charity. For single contributions of $250 or more, you must have a written acknowledgment from the organization showing the amount and whether you received anything in return. For non-cash donations valued at more than $500, complete Form 8283. For donated property worth more than $5,000, you need a qualified appraisal. Never deduct more than the fair market value of donated items, and keep photos or detailed lists for donated goods.

Q7: Do I need to attach receipts and documentation when I mail Schedule A?

A: No. Don't attach receipts, Forms 1098, charitable acknowledgments, or other supporting documents unless the IRS specifically requests them. File your Schedule A with your Form 1040, but keep all supporting documentation in your files. The IRS assumes you have proper documentation; if they audit you or send a correspondence requesting proof, you'll provide the documents then. Sending unsolicited documentation only slows processing and increases the chance of documents being lost.

Important Resources

All sources are from official IRS.gov materials for tax year 2020

2015 Schedule A Form (PDF)
2015 Schedule A Instructions (PDF)
IRS Schedule A Information Page
IRS Amended Returns Information
For specific questions about your tax situation, consult a tax professional or contact the IRS directly at 1-800-829-1040.

This guide is for informational purposes only and does not constitute tax advice. Tax laws are complex and individual situations vary. Always consult with a qualified tax professional for advice specific to your circumstances.